Since Rosh Chodesh falls on motza’ei Shabbos, I thought it appropriate to discuss:

Do I say Yaaleh Veyavo, Retzei or both?

Question #1: Is it Shabbos versus Rosh Chodesh?

“When Rosh Chodesh begins on motza’ei Shabbos, do I say Yaaleh Veyavo in bensching at seudah shelishis?”

Question #2: Why is this night of Chanukah different from all other nights?

“Chanukah begins this motza’ei Shabbos. If I finish seudah shelishis after nightfall, do I include Al Hanissim in bensching?”

Introduction

When we recite birchas hamazon on Shabbos, Yom Tov, Chol Hamoed, Rosh Chodesh, Chanukah and Purim, we include special prayers to commemorate the holiday: on Shabbos, a passage beginning with the word Retzei; on Yom Tov, Chol Hamoed and Rosh Chodesh, the opening words are Yaaleh Veyavo; and on Chanukah and Purim, Al Hanissim.

In a different article, I discussed whether one recites these additions when one’s meal was divided between a holiday and a weekday – i.e., one ate part of his meal on the holiday and part before or after; or when the change of date transpired between the eating of the meal and the bensching. Does one recite the special addition to commemorate the holiday when this happens, or does one omit it? We discovered that there are several opinions as to what to do. These are the earliest opinions that I found:

1. When one bensches

The Rosh rules that one recites the version of birchas hamazon appropriate to when one bensches, regardless as to when one ate the meal. In his opinion, one who finished seudah shelishis after nightfall does not recite Retzei. Similarly, one whose Purim seudah ends after Purim does not recite Al Hanissim. The Rosh also holds that someone who completed a meal before Rosh Chodesh and bensches after it is dark should recite Yaaleh Veyavo.

2. The beginning of the meal

The Maharam, as understood by the Bach and the Aruch Hashulchan, maintains that the text of the bensching is established according to what was correct when the meal began. Therefore, one who finished seudah shelishis after nightfall recites Retzei, since his meal began on Shabbos. (There is an exception – if he did something to declare that Shabbos is over, such as reciting havdalah, davening maariv, or even simply answering borchu, he does not recite Retzei any more, as it is therefore inconsistent to mention Shabbos in bensching.)

3. All of the above

The Maharam, as understood by the Taz, contends that one adds the special prayer if either the meal began on the holiday or one is bensching on the holiday. Thus, one who finished seudah shelishis after nightfall recites Retzei, and someone who completed a meal before Rosh Chodesh and bensches after it is dark should recite Yaaleh Veyavo.

The halachic conclusion

The halachic consensus regarding someone who began his meal on Shabbos or Purim and continued it into the night is that one recites Retzei or Al Hanissim, following the position of the Maharam and not the Rosh.

Conflicting prayers

The topic of our current article adds a new aspect to this question – what to do when Rosh Chodesh or Chanukah begins on motza’ei Shabbos, and seudah shelishis started on Shabbos and was completed on Rosh Chodesh or on Chanukah. According to the Rosh, one should recite Yaaleh Veyavo or Al Hanissim, whether or not one ate on Rosh Chodesh or on Chanukah. However, the consensus of halachic opinion is that the Maharam’s opinion is accepted, in this topic, over that of the Rosh. According to those who understand that the Maharam ruled that one should always recite the text of birchas hamazon appropriate to the beginning of the meal, one should recite Retzei. Yet, many authorities follow the second interpretation of the Maharam mentioned above, that one adds the special prayer if either the meal began on the holiday or one is bensching on the holiday. What complicates our question is that there may be a requirement to recite both Retzei and either Yaaleh Veyavo or Al Hanissim, yet mentioning both in the same bensching might be contradictory in this instance, since the holiday begins after Shabbos ends. As we will soon see, whether or not this is a problem is, itself, debated by the authorities.

The earliest authority that I found who discusses this predicament is the Bach (end of Orach Chayim, 188). Regarding what to recite when seudah shelishis continues into Rosh Chodesh, he concludes that one should say Retzei and not Yaaleh Veyavo, because the beginning of a meal determines the exact text of its birchas hamazon. As I mentioned above, this is precisely the way the Bach understands the Maharam’s position – that the proper bensching is always determined by the beginning of the meal. Since the halacha follows the Maharam’s position, the Bach comfortably rules according to his understanding of the Maharam, that one recites Retzei and not Yaaleh Veyavo.

The Magen Avraham (188:18; 419:1) analyzes the issue differently from the way the Bach does. First, he considers the possibility that one can recite both Retzei and Yaaleh Veyavo. This is based on his understanding of the Maharam’s position that ending a meal on Rosh Chodesh or a different festival is reason to recite the holiday additions, even if the meal started on a weekday. However, the Magen Avraham concludes that one cannot recite both Retzei and Yaaleh Veyavo in this instance, because this is an inherent contradiction: If it is already Rosh Chodesh, it is no longer Shabbos, and if it is still Shabbos, it is not yet Rosh Chodesh. Since this is now a conundrum, the Magen Avraham concludes that one should follow the Rosh’s opinion, that one recites whatever is appropriate to be said at this moment, which means to recite only Yaaleh Veyavo. Magen Avraham contends that this practice is followed only when one ate bread on Rosh Chodesh. If he did not eat bread on Rosh Chodesh, then he should say only Retzei, following the Maharam’s opinion that the special prayers are determined by the beginning of the meal.

Chanukah on motza’ei Shabbos

The Magen Avraham also rules that there is a difference in halachah between Rosh Chodesh and Chanukah. When Chanukah begins on motza’ei Shabbos and seudah shelishis extended into the beginning of Chanukah, he rules that one should recite only Retzei and not Al Hanissim, even if he ate bread on Chanukah.

Why is Chanukah different from all other nights?

The Magen Avraham explains that, whereas when reciting Yaaleh Veyavo on a weekday Rosh Chodesh bensching is required, reciting Al Hanissim in bensching of a weekday Chanukah is technically not required, but optional. Therefore, when his meal began on Shabbos (which was as yet not Chanukah) and he is, therefore, required to recite Retzei, even if he continued the meal into Chanukah and ate bread then, the optional addition of Al Hanissim does not cancel the requirement to recite Retzei.

More opinions

Thus far, we have seen two opinions concerning what to do for the bensching of a seudah shelishis that extended into Rosh Chodesh that begins on motza’ei Shabbos:

(1) The Bach, that one should recite Retzei and not Yaaleh Veyavo.

(2) The Magen Avraham, that if he ate bread on motza’ei Shabbos he should recite Yaaleh Veyavo, but otherwise he should recite Retzei.

A third position is that, once it is Rosh Chodesh, one should recite Yaaleh Veyavo and not Retzei (Maharash of Lublin, quoted by Shelah and Taz 188:7). The Maharash maintains that since at the time he bensches it is Rosh Chodesh, the requirement to recite Yaaleh Veyavo is primary and preempts the requirement to recite Retzei, which he considers to be secondary, since it is no longer Shabbos.

Why not both?

The Taz (188:7) disagrees with all the above-mentioned positions, challenging the assumption that one cannot recite both Retzei and Yaaleh Veyavo. He concludes that since Yaaleh Veyavo is recited after Retzei there is no contradiction, since Rosh Chodesh begins after Shabbos ends. Therefore, one who ate on Shabbos and is bensching on Rosh Chodesh should recite both additions.

To sum up, someone whose meal began on Shabbos and is bensching on Rosh Chodesh, should:

• recite Yaaleh Veyavo, according to both the opinion of the Rosh and that of the Maharash,.
• recite Retzei, according to the opinion shared by the Bach and the Aruch Hashulchan.
• recite both Retzei and Yaaleh Veyavo, according to the conclusion of the Taz,.

According to the ruling of the Magen Avraham, if he ate bread after Rosh Chodesh arrived, he should recite Yaaleh Veyavo. If he did not, he should recite Retzei.

Rabbi, what should I do?

The Mishnah Berurah (188:33), when recording what to do, implies that one should follow the position of the Magen Avraham. He then mentions the Taz as an alternative approach – that one should say both Retzei and Yaaleh Veyavo. This is consistent with the Mishnah Berurah’s general approach of following the Magen Avraham, except when the latter’s position is opposed by most later authorities.

The Aruch Hashulchan, on the other hand, concludes neither as the Magen Avraham nor the Taz, but that what one recites is always determined by the beginning of the meal. Therefore, in this situation, he rules to recite Retzei and omit Yaaleh Veyavo, regardless of whether one ate on Rosh Chodesh.

Since there are many conflicting positions as to which additions to recite when Rosh Chodesh begins on motza’ei Shabbos, many people avoid eating bread after nightfall. They eat all the bread that they intend to eat towards the beginning of the meal, and upon completing the seudah, recite bensching including Retzei and omitting Yaaleh Veyavo. This approach follows the majority of halachic authorities (Bach, Magen Avraham, Aruch Hashulchan, Mishnah Berurah [according to his primary approach]), although it runs counter to the opinions of the Maharash and the Taz. Those who want to avoid any question recite birchas hamazon before the arrival of Rosh Chodesh.

Conclusion

In our daily lives, our hearts should be full with thanks to Hashem for all He does for us. Birchas hamazon provides a regular opportunity to elicit deep feelings of gratitude for what Hashem has done in the past and does in the present. All the more so should we should acknowledge Hashem’s help on special holidays.

Since this coming Shabbos is also Rosh Chodesh, this question may become very germane.

What If I Goofed and Said Tikanta Shabbos by Mistake?

By Rabbi Yirmiyohu Kaganoff

Question: In the middle of davening Musaf on Shabbos Rosh Chodesh, I realized that I was reciting the Musaf for a regular Shabbos rather than the special Musaf for Shabbos Rosh Chodesh. What should I have done?

Answer:

This Shabbos is also Rosh Chodesh, requiring the recital of a special text for the middle bracha of Musaf. This special Musaf includes elements of the usual Shabbos Musaf, the usual Rosh Chodesh Musaf, and a special introductory passage. This passage, beginning with the words Atah Yatzarta, actually bears closer resemblance to the introductory part of the Yom Tov Musaf than it does to Musaf of either Shabbos or Rosh Chodesh. The rest of the middle bracha of Musaf combines elements of both Shabbos Musaf and Rosh Chodesh Musaf.

I once edited an article in which the author quoted several anthologies, each of which ruled that someone who realizes he is saying Tikanta Shabbos on Shabbos Rosh Chodesh should immediately stop where he is, and go to the beginning of Atah Yatzarta, and recite the entire bracha. However, I believe that this ruling is in error. I will explain shortly why I believe that this answer is erroneous.  But first…

I attempted to trace the sources quoted in the article to see if perhaps I was missing some logic or information that I would clarify in the course of my research.

What I did discover was that each source was simply quoting a previous one, and that they all traced to one obscure 19^th century work, which did not explain at all the reason for the ruling. Classic group-think.

I will now explain why I believe this ruling is in error, and what one should do. My major concern is that the approach that these works advocate results in repeating many parts of the shemoneh esrei, and that this repetition constitutes a forbidden interruption in the tefillah. Furthermore, to the best of my knowledge, there is no essential requirement to recite this middle bracha of the shemoneh esrei precisely in order. Obviously, one should maintain the order as is, but there is ample evidence from major halachic authorities that, in general, mistakenly rearranging the order of a bracha is not calamitous (see, for example, Rosh, Taanis 1:1; Shu”t Igros Moshe, Orach Chayim 4:18 and 4:70:14). Thus, when left with the choice of rearranging the order of a bracha to avoid repetition, or repeating parts of the bracha and ignoring what was already said, one should follow the first approach.

Subsequently, I realized that the position I have followed, is indeed that of Rav Moshe Feinstein. However, it appears that, in general, there are other halachic authorities who feel that the text of a brocha should indeed be kept intact even when repetition will result (see, for example, Mateh Efrayim 582:10; Mishnah Berurah 582:16; Biur Halacha 127:2 s.v. Aval).

Notwithstanding the disputing opinion, I still think that the approach I am suggesting is correct, but I recognize that others may disagree with me. Therefore, I am going to present my approach, as confusing as it may appear.

Based on my opinion, it appears that someone who discovers that he/she began reciting Tikanta Shabbos rather than Atah Yatzarta should mention only those parts of the bracha that he/she has as yet not recited, but not repeat any theme or part of the bracha that one has already said. Although fulfilling this may be confusing to someone unfamiliar with the bracha, this should provide us with a valid reason to pay more attention to the details of this bracha and understand its different parts.

In order to explain how one does this correctly, brachos of Atah Yatzarta and Tikanta Shabbos into their constituent parts, so that we can identify which parts we should not repeat. We can divide these brachos into the following seven sections (the sections for a regular Shabbos have been numbered in a way that parallels the list for Shabbos Rosh Chodesh:

We should note that the closings of these middle brachos of Musaf shemoneh esrei are very different. On Shabbos Rosh Chodesh we recite a version that is almost identical to what we recite on a weekday Rosh Chodesh, but we insert three passages to include Shabbos.

Parts 2, 4 and 6 of the two brachos are identical, whether it is Shabbos or Shabbos Rosh Chodesh. Therefore, one should not repeat these sections if one has said them already.

Part 1 on Shabbos Rosh Chodesh, Atah Yatzarta, is very different from what we usually recite on a regular Shabbos. Therefore, someone still in the middle of this bracha should recite this passage again.

If someone missed part 5, mention of the pesukim of Rosh Chodesh, and is still in the middle of this bracha, he/she should recite it and introduce it with the section 3 above, which introduces the korbanos of the Musaf. However, if he/she already recited the pesukim of Shabbos korban Musaf (#4) above, he should omit the reference to Shabbos in this piece and only mention Rosh Chodesh. In the latter case, one should change the plural Musafei to a singular Musaf since he/she now is only mentioning the Rosh Chodesh Musaf.

Having explained the rules governing these halachos, I will now present the conclusions in a hopefully clearer way, depending on when you discover your mistake:

1. If you were still reciting the beginning of Tikanta Shabbos, and had not yet reached Yehi Ratzon:

Return to Atah Yatzarta and recite it in order without any changes.

1. If you had already begun the Yehi Ratzon, but are before Ve’es Musaf Yom HaShabbos Hazeh:

Complete the Yehi Ratzon until Ve’es Musaf; then recite Atah Yatzarta until the words Yehi Ratzon, then resume from the words Ve’es Musafei Yom HaShabbos Hazeh Veyom Rosh Hachodesh from the Shabbos Rosh Chodesh Musaf and continue through the rest of the tefillah.

1. If you had just begun Ve’es Musaf Yom HaShabbos Hazeh:

Add the words Ve’es Musaf Yom Rosh Hachodesh Hazeh, and then continue in the Shabbos Rosh Chodesh Musaf until Yismechu Vemalchusecha. Immediately prior to saying Yismechu Vemalchusecha insert the words from Atah Yatzarta until the words shenishtalcha bemikdashecha. Then return to Yismechu Vemalchusecha and recite the rest of the tefillah in order.

1. If you are already in the middle of Ve’es Musaf Yom HaShabbos Hazeh:

Recite Uveyom Hashabbas… until Veniskah. Then insert the words from Atah Yatzarta until the words shenishtalcha bemikdashecha. Then return to the words Ve’es Musaf but say the following: Ve’es Musaf Yom Rosh Hachodesh Hazeh until the word ka’amur. Then say Uverashei Chadsheichem in the Shabbos Rosh Chodesh section and continue in order.

1. If you are in the middle of Yismechu Vemalchusecha, complete it until Zeicher lemaasei vereishis, and then insert the words from Atah Yatzarta until the words shenishtalcha bemikdashecha. Then return to the words Ve’es Musaf but say the following: Ve’es Musaf Yom Rosh Hachodesh Hazeh until the word ka’amur. Then say Uverashei Chadsheichem in the Shabbos Rosh Chodesh section. Then go to Elokeinu Veilokei Avoseinu (after Yismechu Vemalchusecha) and finish the end of the bracha and the davening.
2. If you are already in the middle of the closing part of the bracha (Elokeinu Veilokei Avoseinu) complete the clause that you are saying, and then insert the words from Atah Yatzarta until the words shenishtalcha bemikdashecha. Then return to the words Ve’es Musaf but say Ve’es Musaf Yom Rosh Hachodesh Hazeh until the word ka’amur. Then say Uverashei Chadsheichem in the Shabbos Rosh Chodesh section. Then return to chadeish aleinu beyom hashabbos hazeh es hachodesh hazeh and finish the end of the bracha in the Shabbos Rosh Chodesh section.

If you completed the entire bracha of Tikanta Shabbos, but mentioned in the middle of the bracha some reference to the korban Musaf of Rosh Chodesh, you have fulfilled the requirements of this prayer and you should continue Retzei (see Mishnah Berurah 423:6). If you completed the bracha of Tikanta Shabbos but did not yet begin Retzeih, you should say “vena’aseh lefanecha korban Rosh Chodesh hazeh” – “and we shall do before You this Rosh Chodesh offering” and then continue with Retzei (ibid.).

Conclusion

Although all this may sound very confusing, if we spend a few seconds familiarizing ourselves with the divisions of this bracha that I have made, we will easily realize why the halachos are as I have outlined, and will be ready to make the necessary adjustments should we find that we have erred. This readiness has of course a tremendous value on its own: It familiarizes us with the shemoneh esrei, something we always should do, but, unfortunately, often do not pay sufficient attention.

Understanding how much concern Chazal placed in the relatively minor aspects of davening should make us even more aware of the fact that davening is our attempt at building a relationship with Hashem. As the Kuzari notes, every day should have three high points — the three times that we daven. Certainly, one should do whatever one can to make sure to pay attention to the meaning of the words of one’s Tefillah. We should gain our strength and inspiration for the rest of the day from these three prayers. Let us hope that Hashem will accept our tefillos together with those of Klal Yisrael!

In honor of Rosh Chodesh later this week, and Purim in two more weeks, I present:

Bensching in the Dark on Rosh Chodesh

Question #1: Rosh Chodesh arrival

“I began eating dinner before Rosh Chodesh, but when I finished, it was dark. Do I recite Yaaleh Veyavo?”

Question #2: Rosh Chodesh departure

“I began eating dinner on Rosh Chodesh, but when I finished, it was dark. Do I recite Yaaleh Veyavo?”

Introduction

When we recite birchas hamazon on Shabbos, Yom Tov, Chol Hamoed, Rosh Chodesh, Chanukah and Purim, we include special prayers to commemorate the holiday: On Shabbos, a passage beginning with the word Retzei; on Yom Tov, Chol Hamoed, and Rosh Chodesh, the prayer Yaaleh Veyavo; and on Chanukah and Purim, Al Hanissim. However, it is inappropriate to recite these prayers on an ordinary weekday. What does one do when the date changes between the beginning of the eating of the meal and the bensching? Do we recite the bensching appropriate to the day on which the meal began or appropriate to when the meal ended?

Weekly seudah shelishis

Let us start this discussion with a very common application. Many people eat the last meal of Shabbos, colloquially but not accurately called shalosh seudos, late in the afternoon, finish after dark, and then recite Retzei in bensching. (The correct way to refer to this meal is seudah shelishis or seudah shelishit.) Most of us are unaware that this practice is disputed by early authorities. The Rosh (Shu’t HaRosh 22:6; Pesachim 10:7) asserts that once Shabbos is over, one cannot say Retzei. He compares this to davening a Shabbos prayer after the conclusion of Shabbos, which is certainly inappropriate. Just as the fitting prayer is determined by when one is praying, so, too, the correct text of bensching is determined by when one is reciting it. Similarly, in the Rosh’s opinion, a meal begun on Rosh Chodesh, Chanukah or Purim that continues into the night following the holiday should not include mention of the special day on which the meal began. This position is followed by the Rosh’s son in the Tur (Orach Chayim 695). According to this approach, the common practice of completing the Purim seudah after the day is over and including Al Hanissim in the bensching is incorrect.

A disputing opinion is quoted in the name of the Maharam (see Hagahos Maimaniyos, Megillah 2:14:1), which states that a meal begun on a holiday maintains its special mention, even when one bensches after the day is over. Thus, when one bensches on seudah shelishis after it is dark, one still recites Retzei. Similarly, if one’s Purim seudah extends into the night, one still recites Al Hanissim in the bensching. These laws apply, as well, on Yom Tov, Rosh Chodesh and Chanukah (Shulchan Aruch, Orach Chayim 188:10). The practice, already cited in earlier authorities, of completing the Purim seudah after the day is over and then reciting Al Hanissim is based on this position of the Maharam (Rema, Orach Chayim 695:3).

What is the Maharam’s rationale? According to one approach, his position is based on the concept that one can extend the sanctity of Shabbos, even after the day is technically over (Dagul Mei’revavah, end of Orach Chayim 188).

Of course, the question is how this affects Purim. The Maharam is quoted as ruling that one who began his meal on Purim, and completed it after the holiday is over, should still recite Al Hanissim in bensching. However, there is no Talmudic source to say that Purim has a concept of tosefes kedusha. According to the Dagul Mei’revavah’s approach to understanding the Maharam, one must assume that there is tosefes kedusha on Purim, Chanukah and Rosh Chodesh to the extent that one then recites the appropriate addition to the bensching.

Ending Shabbos before bensching

As we just explained, the Maharam rules that one recites Retzei on motza’ei Shabbos for a meal that began on Shabbos. However, if someone recited havdalah and has not yet bensched for seudah shelishis, he must omit Retzei, since recital of havdalah ends Shabbos. The same is true not only regarding havdalah, which clearly ends Shabbos, but even when one does anything implying that Shabbos is over – such as davening maariv or even simply answering Borchu, since these activities occur only after the conclusion of Shabbos (Shu’t Maharil #56). The Magen Avraham (188:17) notes that someone who davened maariv before Shabbos is over (which is halachically permitted under extenuating circumstances) does not say Retzei when he subsequently bensches, even though he is still required to observe Shabbos (since it is before nightfall). This ruling is followed by the Mishnah Berurah (188:32) and other authorities. The Magen Avraham (263:33) and other authorities are uncertain whether one who said hamavdil bein kodesh lechol after Shabbos is over, but has as yet not bensched after seudah shelishis, may still say retzei.

Halachic deciders

How do the halachic authorities decide regarding the dispute between the Maharam and the Rosh?

The Rema consistently follows the position of the Maharam (Orach Chayim 271:6; 695:3). However, it is a bit unclear how the Shulchan Aruch rules. He discusses these laws in three different places in Orach Chayim. In the laws of bensching (188:10), he concludes according to the Maharam that the structure of the bensching follows the beginning of the meal, whether it is Shabbos, Rosh Chodesh, Purim or Chanukah. When discussing a Purim seudah that continues into the night, the Shulchan Aruch (695:3) cites as the main opinion the position of the Maharam that one recites Al Hanissim in bensching, yet he quotes the Rosh as an alternative opinion that one omits Al Hanissim once Purim is over. However, regarding someone who concludes a meal on Friday afternoon immediately before Shabbos and who will be bensching on Shabbos, the Shulchan Aruch requires the person to include Retzei (271:6), even if he did not eat anything on Shabbos.

The Bach (188 and 695) views the Shulchan Aruch as being inconsistent, arguing that this last decision contradicts the position of the Maharam, which the Shulchan Aruch himself follows in 188 and 695. The Bach understands, as do other authorities (e.g., the Aruch Hashulchan 188:23), that, according, to the Maharam, the essential factor is when the meal began, whereas, according to the Rosh, the determining factor is what day it is at the moment of bensching. According to the Bach’s understanding of the Maharam, someone who began a meal before Shabbos and continued it into Shabbos should omit Retzei, which contradicts the conclusion of the Shulchan Aruch. The Bach’s approach is consistent with the ruling of the Rema.

There are other approaches how to resolve the conflicting rulings of the Shulchan Aruch. The Magen Avraham (271:14) explains that when a ruling is contingent on the dispute between the Maharam and the Rosh, one should say Retzei. That is, someone who eats Friday afternoon and is bensching on Shabbos should say Retzei, following the approach of the Rosh, whereas someone who eats on Shabbos and is bensching after Shabbos should recite Retzei, in accordance with the opinion of the Maharam.

However, other authorities contend that the Shulchan Aruch is following the Maharam consistently, but they understand the Maharam’s position differently from the way the Bach did. Whereas the Bach understood the Maharam to be saying that the sole determinant is when the meal began, they understand that either the beginning of the meal or the time of bensching determines whether we recite the special holiday prayer. In their opinion, if one began a meal on a holiday but bensched only after the holiday was over, one recites the appropriate holiday passage (Taz 188:7; Elyah Rabbah 188:20).

Tosefta

A compromise position

Until now, we have cited two early authorities, the Rosh and the Maharam, as the basic positions on this topic. There are later authorities who present a middle ground that clearly disagrees with both the Maharam and the Rosh (Magen Avraham 188:18, quoting Maharash, quoted by the Shelah and the Eimek Beracha; see also Shu’t Rema 132:5). This approach draws a distinction between a Shabbos meal extending after Shabbos and those of Rosh Chodesh and Chanukah extending after the respective holiday. Since there is a concept of tosefes Shabbos, i.e., the mitzvah to extend the day of Shabbos, the extension of the day retains sanctity, and therefore the meal is still considered a Shabbos meal warranting the recital of Retzei. However, since neither Rosh Chodesh nor Chanukah have a concept of tosefes kedusha, and, in addition, they have no requirement to eat special meals, the special prayer associated with them should not be recited once the day has passed.

Rosh Chodesh arrival

At this point, we can discuss our opening question:

“I began eating dinner before Rosh Chodesh, but when I finished, it was dark. Do I recite Yaaleh Veyavo?”

We need to ask a few questions: Did he eat on Rosh Chodesh? If he did, then according to Magen Avraham, Taz, Elyah Rabbah and Mishnah Berurah he should recite Yaaleh Veyavo, whereas according to the Aruch Hashulchan, and probably several other authorities, he should not. I would personally rule that he should follow the majority opinion and recite Yaaleh Veyavo in this situation.

If he did not eat on Rosh Chodesh, according to the Rosh and Magen Avraham, he should recite Yaaleh Veyavo. I refer our reader to his own posek for an answer what to do under these circumstances.

Rosh Chodesh departure

As far as our second question is concerned: “I began eating dinner on Rosh Chodesh, but when I finished, it was dark. Do I recite Yaaleh Veyavo?”

Assuming that he did not yet daven maariv, according to the Magen Avraham, Taz, Elyah Rabbah, Aruch Hashulchan and Mishnah Berurah, he should say Yaaleh Veyavo, whereas according to the Rosh, Tur, Maharash and Shelah he does not. It would seem to me that, in this instance, the halachah should not be affected by whether he ate after it became dark.

Conclusion

When we show how careful we are to honor Hashem with the appropriate wording of our bensching, we demonstrate our concern and our priorities. Whatever conclusion we reach regarding whether we recite these special inserts, we should certainly pay careful attention to the meaning of the words of one’s bensching at all times.

When the Torah commands us to create a calendar, it includes two different responsibilities: First, to have Rosh Chodesh and the length of each month determined on the basis of when the new moon appears, and, second, to have the holiday of Pesach fall in the spring and the holiday of Sukkos in the autumn (in the northern hemisphere). Thus, we have two separate and very different requirements, one of having the months determined by the moon, which is a little more than every 29½ days, and having years that coordinate with the seasons, which follow the solar year, which is a bit less than 365¼ days.

To accomplish that the dates and holidays should fall according to the seasons, the halacha is that some years have 12 months, or approximately 354 days, and others have 13 months, or approximately 384 days. This ensures that the holidays fall in their appropriate seasons. The mitzvah of the Torah is that the head of the Sanhedrin should be in charge, every month, to decide whether a month is 29 days long or 30, and of deciding whether a year should have an extra month. In the latter case, he appointed a special committee, comprised of members of the Sanhedrin, to review the relevant information and determine whether the year should be 13 months (a leap year) or only 12 (a common year).

By the way, after the destruction of the Beis HaMikdash, the main Beis Din was not located in Yerushalayim, but wherever the Nasi of the Jewish people resided, as long as it was in Eretz Yisrael. This included several communities at various times of Jewish history, including Teverya, Yavneh, and Shafraam.[i] Indeed, during this period, if the head of the Beis Din was in the Diaspora and there was no one of his stature remaining in Eretz Yisrael, the special Beis Din met outside the land of Israel.[ii]

Initially, all these decisions were made by the heads of the Sanhedrin, and, indeed, when Moshiach comes, we will again have this system. This was the system in place for thousands of years – from the time of Moshe Rabbeinu until about 250 years after the destruction of the second Beis Hamikdash. At that time, the head of the Sanhedrin, Hillel Hanasi (not to be confused with his ancestor, Hillel Hazakein), realized that, because of Roman persecution, the Sanhedrin’s days were numbered and it would be necessary to switch to a different system for determining the calendar. Hillel Hanasi implemented a temporary Jewish calendar, which is the one that we currently use. Although many people refer to it as a “permanent calendar,” it will be in use only until we again have a Sanhedrin, which will then be in charge of the calendar.

Hillel’s calendar kept the same basic structure of 29- and 30-day months and 12- and 13-month years, but it is based purely on calculation and not on observation. The two major changes in this new calendar are:

• A Leap of Fate

The leap years now occur following a regular pattern of seven leap years and 12 non-leap (usually called “common”) years in a 19 year cycle. The third, sixth, eighth, eleventh, fourteenth, seventeenth and nineteenth years of the cycle are always leap years, and the rest are common years. This year is the nineteenth year of the cycle, and thus is a leap year.

• The Haves versus the Have-nots

The length of most months is now predetermined. Tishrei, Shvat, Adar Rishon (which exists only in a leap year), Nissan, Sivan and Av always have 30 days; whereas Teiveis, regular Adar (in a common, non-leap year), Adar Sheini (in a leap year), Iyar, Tamuz and Elul are always only 29 days long. The two months of Cheshvan[iii] and Kislev are the only months whose length varies, sometimes 29 days and sometimes 30.[iv] A year in which both Cheshvan and Kislev have only 29 days is called chaseirah, lacking or defective; one in which Cheshvan has 29 days and Kislev has 30 is called kesidrah, as expected or regular; and one in which both Cheshvan and Kislev have 30 days is called sheleimah, full or excessive.

The terms chaseirah, kesidrah, and sheleimah apply in both common and leap years.[v] Thus, in the new calendar, all common years are either 353 days (if both Cheshvan and Kislev have 29 days), 354 days (if Cheshvan has 29 days and Kislev has 30) or 355 days (if both Cheshvan and Kislev have 30 days); all leap years are either 383 days (if both Cheshvan and Kislev have 29 days), 384 days (if Cheshvan has 29 days and Kislev has 30) or 385 days (if both Cheshvan and Kislev have 30 days). Since Adar in a common year always has 29 days, Adar Rishon always has 30 days, and Adar Sheini always has 29 days, like the regular Adar, the addition of an extra month of Adar in a leap year always adds exactly thirty days.

(Because the nineteen-year cycle synchronizes the lunar calendar with the solar year, the Hebrew and English dates of births, anniversaries and other occasions usually coincide on the nineteenth anniversary of the event. If yours does not, but is off by a day or two, do not fret. Your record keeping is accurate, but the cycle of nineteen years only relates to whether it is a leap year, not to whether the years are of the exact same length. The lengths of Cheshvan and Kislev are determined by other factors, and this will affect whether your 19^th, 38^th or 57^th birthday or anniversary exactly coincides with its Hebrew/secular counterpart, or whether it is slightly off.)

The new calendar bases itself on an estimate, an average time that it takes the moon to revolve around the Earth. This molad calculation is that each new moon appears 29 days, 12 hours, and 793 chalakim (singular: chelek) or 793/1080 of an hour after the previous new moon. Once one knows when the new moon, called the molad, occurred on the previous Rosh Hashanah, one could now add either 12 or 13 times the above figure and determine the time of the molad in the next year, which is the most important factor in determining the date of the next Rosh Hashanah. (The term chelek, used on Shabbos Mevorchim when announcing when the molad is, equals 1/1080 of an hour, or 3 and 1/3 seconds.)

There is one other factor: Sometimes Rosh Hashanah takes place not on the day of the molad, but the next day, because the molad occurred on the afternoon of Rosh Hashanah and would not be visible in Eretz Yisrael until the next day. When Rosh Hashanah was determined by the observation of witnesses, this information was important not only in determining when Rosh Hashanah falls, but also for interrogating potential witnesses testifying to the appearance of the new moon. However, Hillel’s calendar is no longer dependent on witnesses, Rosh Hashanah is still not established on a day when the molad falls on its afternoon, but is postponed. Based on this information, one can determine which day should be Rosh Hashanah in the coming year.

Another major innovation

Did you ever notice that Yom Kippur never falls on Friday or Sunday? If it did, we would observe two consecutive days that both have the stringency of Shabbos. Indeed, when the calendar was based on observation, this could and did happen.[vi]

However, Hillel Hanasi’s calendar included some innovations that were not part of the earlier calendar. His calendar does not allow Yom Kippur to fall on either a Sunday or a Friday, thus avoiding the difficulty of having two Shabbos-like days fall consecutively. Hillel Hanasi’s calendar also does not allow Hoshana Rabbah to fall on Shabbos, which would cause the cancellation of the Hoshanos ceremony. As long as the calendar was determined on the basis of eyewitness testimony, it was halachically more important to have Rosh Chodesh fall on its correct day than to be concerned about difficulties created when certain holidays fall on or next to Shabbos.[vii] However, once we are fulfilling the mitzvah in a less-preferred way with Hillel’s “permanent” calendar, keeping Yom Kippur from falling on Friday or Sunday, and Hoshana Rabbah from falling on Shabbos, are factors to be included in establishing the calendar.

In order to accommodate these innovations, Rosh Hashanah could fall only on Monday, Tuesday, Thursday or Shabbos, since if it falls on Sunday, Hoshana Rabbah falls on Shabbos; if Rosh Hashanah falls on Wednesday, Yom Kippur falls on Friday; and if Rosh Hashanah falls on Friday, then Yom Kippur falls on Sunday. This would mean that when Rosh Hashanah in the coming year would naturally fall on Sunday, Wednesday or Friday, an extra day is added to the calendar to make sure that Rosh Hashanah falls on Monday, Thursday or Shabbos instead.[viii] This calendar concept of guaranteeing that Rosh Hashanah not fall on Sunday, Wednesday or Friday is called לא אד”ו ראש, lo adu rosh, meaning that the beginning of the year, Rosh Hashanah, does not fall on א, the first day of the week, Sunday; ד, Wednesday; or ו , Friday. It is predominantly for this reason that there was a need to have Cheshvan and Kislev sometimes 29 days and sometimes 30, in order to make the exact length of the years flexible.

Although the innovation of adding one day to the year so that Rosh Hashanah not fall on a Sunday, Wednesday or Friday seems relatively simple, it sometimes leads to more complex considerations. In some years, adjusting Rosh Hashanah to avoid Sunday, Wednesday and Friday creates a problem in the year before or the year after. Since Hillel Hanasi’s calendar did not allow a common year to be longer than 355 days and a leap year to be shorter than 383 days, the only way to avoid problems is to plan the calendar an additional year in advance and adjusting the calendar appropriately. In order to accomodate all these various calendar requirements, Hillel Hanasi established four rules, called dechiyos, which, together with the sod ha’ibur calculation and the 19 year leap year rotation, form the basis for determining our calendar.[ix]

To explain how this works, let us choose a sample year in which the molad calculation for Rosh Hashanah fell on Wednesday evening, and Rosh Hashanah therefore falls on Thursday, which is what we would expect. However, the next year’s molad for Rosh Hashanah falls on Tuesday less than two hours before the end of the day. Although the molad falls on Tuesday, it is too late in the day for this molad to be visible in Eretz Yisrael, and therefore, Rosh Hashanah cannot occur before Wednesday. However, since Rosh Hashanah cannot fall on a Wednesday because of the rule of lo adu rosh, it must be pushed off to Thursday, or two days after the molad. For this reason, that year must have an extra day. However, each year is limited how long it may be. In order to accommodate the proper dating of the second year, the year prior would have to have more days than the calendar allows. In order to resolve this, the year before is made longer than necessary. What is happening is that one Rosh Hashanah is postponed to allow that the next Rosh Hashanah should fall out in an acceptable way.

As I mentioned above, although the leap years follow an absolute nineteen-year cycle, whether the year is chaseirah, kesidrah, or sheleimah is determined by the other factors we have noted, and therefore does not follow the nineteen-year pattern. Rather, one first calculates when Rosh Hashanah should fall out based on the sod ha’ibur, checks the rules of the dechiyos to see what adjustments need to be made, and then determines on which day Rosh Hashanah should fall. As a result, whether the year in question needs to be chaseirah, kesidrah, or sheleimah requires calculating not only this year’s schedule, but also the coming year’s calendar requirements.

Based on all these calculations, there are seven prototype years for a common year and seven for a leap year that fulfill the calendar rules. Each of these fourteen prototype “years” is called by a three letter acronym in which the first letter identifies the day of the week of the first day of Rosh Hashanah, the second letter denotes whether the year is chaseirah, kesidrah, or sheleimah, and the third letter identifies the day of the week of the first day of Pesach. No letter is used to denote whether the year is common or leap, because this is understood by knowing how many days of the week Pesach follows Rosh Hashanah. In a common year that is kesidrah, Pesach falls two days later in the week than Rosh Hashanah, and in a leap year, it falls four days later, the two additional days being the extra two days that the extra month of Adar Rishon, thirty days long, adds to the day of the week count. Of course, these calculations must be adjusted one day in either direction, if the year is chaseirah or sheleimah. Either way, calculating how many days are between Rosh Hashanah and Pesach tells us whether it is a common or leap year, so there is no need to include this in the acronym.

Thus, this year 5776 is known as בשז because Rosh Hashanah fell on Monday (ב), it is a sheleimah (ש) year in which both Cheshvan and Kislev contain 30 days, and the first day of Pesach falls on Shabbos (ז).

At this point, we have the basic information to figure out how our calendar operates. Although we may not realize it, we actually already have enough information at our fingertips that we could already calculate the calendars for the coming years – indefinitely.

Conclusion

We understand well why our calendar involves use of the solar year – after all, our seasons, and the appropriate times for our holidays, are based on the sun. But why did the Torah insist that our months follow the moon? It seems that we could live fine without months that are dependent on the moon’s rotation around the earth!

One answer to this question is that the waxing and waning of the moon is symbolic of our own our relationship with Hashem – which is sometimes better and sometimes less so. However, we know that we can always improve that relationship, just as the moon after its waning and almost disappearing always renews itself.

[i] Rosh Hashanah 31b

[ii] Berachos 63a; Rambam, Hilchos Kiddush HaChodesh 1:8

[iii] Although the correct name of the month is Marcheshvan, we will follow the colloquial use of calling it Cheshvan.

[iv] Rambam, Hilchos Kiddush Hachodesh 8:5

[v] By the way, because Kislev is sometimes 29 days and sometimes 30, the last day of Chanukah is sometimes on the second day of Teiveis, and sometimes on the third.

[vi] She’iltos of Rav Acha’ei Geon, #67; Rambam, Hilchos Shabbos 5:21; Ha’emek She’eilah ad loc., Note 22.

[vii] Ha’emek She’ailah ibid; Gri”z, Hilchos Kiddush Hachodesh

[viii] Rambam, Hilchos Kiddush Hachodesh 7:1.

[ix] Because these dechiyos are extremely technical, I did not explain all of them.

 Question #1: An Unusual Bessing

“Why does Shabbos Rosh Chodesh have a completely different middle beracha rather than simply having a Rosh Chodesh insert in the Shabbos davening or vice versa?”

Question #2: Missing my Chatas

“Why is no korban chatas offered on Shabbos?”

Question #3: Shortchanged Yom Tov

“Why is Rosh Chodesh the only special day mentioned in the Torah that is not a Yom Tov?”

Answer:

When a holiday falls on Shabbos, the tefillah that we recite is usually the regular prayer either of the holiday or of Shabbos, with an addition or additions to include mention of the other special day. For example, when the major Yomim Tovim (Sukkos, Pesach, Shevuos, Rosh Hashanah and Yom Kippur) fall on Shabbos, we recite the regular Yom Tov prayer, with added mention of Shabbos in the middle beracha. On the lesser holidays (Chol Hamoed, Rosh Chodesh, Chanukah and Purim), for most tefillos we recite the customary Shabbos prayer and add an extra paragraph, either Yaaleh Veyavo or Al Hanissim, at its appropriate place, to reflect the sanctity of the holiday. On Musaf of Shabbos Chol Hamoed, we recite the Musaf of Yom Tov with added mention of Shabbos in the middle beracha.

Ata Yatzarta — A Special Prayer

The one exception to this rule is the Musaf that we recite when Rosh Chodesh falls on Shabbos. On Shabbos Rosh Chodesh, the middle beracha of the Musaf is an entirely new beracha that does not simply combine the elements of the Shabbos Musaf and that of the weekday Rosh Chodesh Musaf. Rather, it includes aspects of the Musaf of Yom Tov, and the prayer includes a unique introduction that appears is in no other prayer. Thus, the sum is greater than its parts – the combination of Shabbos and Rosh Chodesh creates a greater kedusha than either has on its own. Explaining this phenomenon is the thrust of this week’s essay, but first I need to explain certain themes more thoroughly.

Background to Musaf

To understand the tefillah of Ata Yatzarta better, we first need to understand why Shabbos, Rosh Chodesh and the Yomim Tovim are embellished with a tefillah called Musaf. Each of our three daily tefillos, Shacharis, Mincha, and Maariv corresponds to a part of the service that was performed daily in the Beis Hamikdash (Berachos 26b). Musaf corresponds to the special korbanos described in parshas Pinchas that were offered in the Beis Hamikdash on Shabbos, Rosh Chodesh and holidays.

A Review of Rosh Chodesh Musaf

With this background, we can now examine the unique text of the Shabbos Rosh Chodesh Musaf. As I mentioned above, the central beracha of this tefillah is unusual in that it contains aspects of four different themes. The beracha begins with a declaration, Ata Yatzarta Olamcha Mikkedem, “You fashioned Your world from the very beginning,” a declaration that certainly reflects the inherent concepts of both Shabbos and Rosh Chodesh; yet, this declaration appears in none of the four regular Shabbos tefillos nor in the weekday Rosh Chodesh Musaf. This is highly unusual, particularly when we realize that, on all other occasions when Shabbos coincides with another special day, the wording of the prayers always reflects the exact text of either Shabbos or Yom Tov, and never a new version.

The special Musaf beracha then proceeds: Ahavta osanu veratzisa banu, “You loved us and desired us,” a text that appears in the Musaf of Yom Tov. Again, this is unusual, since this wording never appears either in the usual Shabbos or in the usual Rosh Chodesh prayers. How does a theme unique to Yom Tov find its way into Shabbos Rosh Chodesh, which is not a Yom Tov?

The next sentence, beginning with the words Vehi ratzon, is a text that is common to both the Shabbos and the Yom Tov Musaf prayers, and this passage then introduces the actual korbanos of both Shabbos and Rosh Chodesh. From this point onward, the prayer continues along predictable patterns, blending together the Musaf of a common Shabbos and a weekday Rosh Chodesh into one beracha commemorative of both occasions.

Yismechu Bemalchuscha

Included in the Ata Yatzarta prayer is the passage, Yismechu bemalchuscha shomrei Shabbos, “Those who observe the Shabbos shall celebrate Your kingship,” a special prayer that the Jewish people enjoy their celebration of Shabbos as they recognize Hashem’s dominion and beneficence. In Nusach Ashkenaz, this prayer is recited every Shabbos Musaf, even when Shabbos coincides with Yom Tov or Rosh Chodesh. Nusach Sfard includes this passage also in Maariv and Shacharis of Shabbos. (The Avudraham records a custom in some communities not to recite Yismechu bemalchuscha in regular Shabbos Musaf and to recite it only on Shabbos Rosh Chodesh. The Avudraham himself disapproves of this practice, and I am unaware of any community that follows this custom today.)

Closing the Beracha

Returning to Ata Yatzarta, we close this beracha with a text that is standard for the central beracha of all Shabbos and Yom Tov prayers. The conclusion of the middle beracha of Musaf always notes the special features of the day we are celebrating.

Why Ata Yatzarta?

At this point, we can address the original question we posed: “Why does Shabbos Rosh Chodesh merit its own special Musaf prayer, rather than simply having a Rosh Chodesh insert in the Shabbos davening, or vice versa?”

To explain why we recite the unique beracha of Ata Yatzarta, we need first to understand that each korban Musaf reflects something special about that day. An obvious example is the offering of bulls that is incorporated in the korbanos Musaf of the seven days of Sukkos. Over the seven days of Sukkos, we offer seventy bulls as part of the Musaf in a particular order, beginning with thirteen on the first day and decreasing by one each day until we offer seven on Hoshanah Rabbah, the last day of Sukkos. These seventy bulls correspond to the seventy nations of the Earth who descended from Noah. Thus, one theme of Sukkos is that our korbanos service is to benefit not only the Jewish People, but for the sake of the world and its entire population.

One unusual goat

The vast majority of korbanos offered as part of the Musaf are korbanos olah, which, Rav Hirsch explains, are to assist in our developing greater alacrity in observing Hashem’s commandments (Commentary to Shemos 27:8). In addition to the many korbanos olah offered as part of the Musaf of Rosh Chodesh and of all Yomim Tovim, there is also always one goat offered as a korban chatas. A chatas is usually translated as a “sin offering” and, indeed, in most instances its purpose is to atone for specific misdeeds. The offering of a korban chatas on every Yom Tov and Rosh Chodesh provides specific atonement on that day that we cannot accomplish on an ordinary weekday (see Mishnah, Shevuos 2a; also see Vayikra 17:10 and Rashi ad loc.).

The Shabbos Musaf

However, the Musaf offering for Shabbos contains no korban chatas. As a matter of fact, Shabbos is the only special day mentioned by the Torah on which a korban chatas is not offered. Clearly, the purpose of Shabbos is not to atone, but to commemorate the fact that Hashem created the entire world in the six days of Creation and then stepped back. Thus, observing Shabbos is our acknowledgement of Hashem as Creator of the Universe, but the discussion of sin and its atonement is not part of the role of Shabbos.

Uniqueness of Rosh Chodesh

The celebration and role of Rosh Chodesh in our calendar is different from Shabbos or any of the Yomim Tovim, since the monthly waning and waxing of the moon that Rosh Chodesh commemorates symbolizes that people occasionally wane and wax in their service of Hashem (Rav Hirsch’s Commentary to Shemos 12:1-2). Although we sometimes falter or are not as devoted to serving Hashem as we should be, we always can and do return to serve Him. Rosh Chodesh is celebrated at the first glimmer after the disappearance of the moon, after one might lose all hope. The reappearance of the first sliver of the new moon brings hope that, just as the moon renews itself, so, too, we can renew our relationship with Hashem. The chatas offering of Rosh Chodesh, therefore, allows atonement for our shortcomings of the past month, and, at the same time, reminds us to focus on our mission as Hashem’s Chosen People.

Uniqueness of the Rosh Chodesh Korban Musaf

The Musaf of each of the Yomim Tovim also includes a korban chatas, and each Yom Tov therefore includes a concept of judgment and atonement (Mishnah, Rosh Hashanah 16a; Mishnah, Shevuos 2a). However, the Torah’s description of the korban chatas of Rosh Chodesh differs from its description of the korbanos chatas that are offered on the other Yomim Tovim. The chata’os of the other Yomim Tovim are always mentioned immediately after the other Musaf offerings of the day. However, when the Torah teaches about the Musaf of Rosh Chodesh, the Torah first lists the other Musaf offerings, then sums up with the statement, Zos olas chodesh bechodsho lechodshei hashanah, “these are the olah offerings of Rosh Chodesh for all the months of the year,” as if it has completed the discussion of the Musaf for Rosh Chodesh. Only then does the Torah mention the chatas offering, implying that the chatas of Rosh Chodesh fulfills a unique purpose – almost as if it stands alone.

More significantly, the wording of the chatas of Rosh Chodesh is different from that of the other chatas offerings. Whereas in reference to all the chata’os of Yom Tov the Torah simply says that one should offer a chatas, on Rosh Chodesh the Torah says that one should offer a chatas to Hashem (Rav Hirsch’s Commentary to Bamidbar 28).

The Gemara itself notes this last question and provides a very anomalous answer: Hashem said, this goat is atonement for My decreasing the size of the moon (Shevuos 9a). From here, Chazal derive that the sun and moon were originally created equal in size, and that later Hashem decreased the size of the moon.

This statement sounds sacrilegious – how can one imply that something Hashem did requires atonement?

Indeed, I have seen commentaries say that the explanation of this Gemara is kabbalistic and should be left for those who understand these ideas.

Others explain that the korban that the Jews offer on Rosh Chodesh appeases the moon for its stature being decreased (Ritva, Shevuos 9a). What does this mean?

Man’s Relationship with G-d

This could be understood in the following way: Rav Hirsch (Commentary to Bamidbar 28) explains that the “atonement for decreasing the moon” means that Hashem created Man with the ability to sin, and thereby he can create evil and darkness. For, after all, sins committed by human beings are the only evil in the world. Thus, someone might “accuse” Hashem of creating evil, by creating Man with the ability to sin. This can be called “decreasing the size of the moon,” since the moon’s waning and waxing carries with it the meaning of the waning and waxing of the relationship of Man to Hashem.

However, the message of the chatas of Rosh Chodesh is that Man can return to serve Hashem, and that, on the contrary, this was the entire purpose of Creation. In error, someone might have accused Hashem of having brought sin into the world, and therefore decreasing the moon. In reality, Man’s serving Hashem is the only true praise to Him. The offering of the korban chatas on Rosh Chodesh demonstrates this. Indeed, man is fallible, but when fallible man serves Hashem this demonstrates the truest praise in the world for Him.

Why Rosh Chodesh is not Yom Tov

According to a Midrash, prior to the debacle of the Jews worshipping the Golden Calf, the eigel hazahav, Rosh Chodesh was to have been made into a Yom Tov. Unfortunately, when the Jews worshipped the eigel hazahav, this Yom Tov was taken from them and presented exclusively to the women, who had not worshipped the eigel (Tur, Orach Chayim 417, and Mahalnach commentary ad loc.). The sin of the eigel hazahav demonstrates how low Man can fall. This is symbolically represented by the decrease of the moon. As a result of this sin, Rosh Chodesh could not become a Yom Tov, but had to remain a workday.

However, when Shabbos and Rosh Chodesh coincide, no melacha is performed on Rosh Chodesh, so that it can now achieve what it would have accomplished as a Yom Tov. This is the goal of a Shabbos Rosh Chodesh, and for this reason, we include a Yom Tov aspect to our davening.

And not only does Shabbos increase the sanctity of Rosh Chodesh, but Rosh Chodesh increases the sanctity of Shabbos. The Gemara conveys this idea by declaring that the korban Musaf of Shabbos has more sanctity when Shabbos falls on Rosh Chodesh (Zevachim 91a).

Conclusion

Shabbos is our acknowledgement of Hashem as Creator of the Universe, whereas Rosh Chodesh demonstrates the role of mankind as the purpose of the Creation of this world. Since Man is the only creation capable of sinning, he is the only one able to make a conscious choice to serve his Maker.

Based on this, we can understand why the coming of Shabbos, which demonstrates the Creation of the universe, together with Rosh Chodesh, which demonstrates Man’s role in Creation warrant a special beracha and a special declaration Ata Yatzarta, You created the world.