Geneivas Da’as

Question #1: “Stealing” Minds

How do you “steal someone’s mind”? Is that like borrowing his brains?

Question #2: Potential Guests

May I invite someone for a meal, knowing that he always declines invitations?

Question #3: Mistaken Identity

Someone donated money to our organization, but it is clear that she did not realize what we do. Must I bring this to her attention?

Question #4: Permission to Deceive

Am I ever permitted to be deceptive?


When someone deceives his fellowman, he may violate two different prohibitions of the Torah. The first is called ona’ah, cheating or taking unfair advantage. Selling something that is definitely worth less than the money received qualifies as ona’ah that the Torah forbids. This includes selling merchandise that is defective in a non-obvious way, or engaging in a transaction on the basis of insider information. It also includes over-presenting a product or disguising its blemishes.

In most circumstances, if ona’ah was violated, the cheated party has a halachic right to get his money back or to be compensated the difference in value. There are many more details concerning the prohibition of ona’ah, which I discussed in a previous article, How Much May I Charge.

Geneivas da’as

This article will deal with a different form of deception called geneivas da’as, literally “stealing a mind.” This means that a person misleads someone else concerning a matter or item. This is prohibited, even when the deceived party does not lose money or value as a result. It applies even in non-financial matters; intentionally misleading someone is prohibited as geneivas da’as.

There are several halachic differences between ona’ah and geneivas da’as. As I mentioned above, if a situation violates ona’ah, the cheated party may be entitled to invalidate the entire sale, or to receive back the amount of the deception. (In some instances when the amount of deception is small relative to the value of the sale, halacha does not require restitution. I refer you to the above-referenced article.) On the other hand, geneivas da’as does not require restitution, since there was no direct financial benefit as a result of the deception that occurred.

Here are a few examples of geneivas da’as:

Deception without cheating

1. The deceiver convinces his customer that the item has a benefit that it does not have. This is forbidden, even though the feature does not increase the item’s sale value.

2. Misleading a customer to think that he is getting a bargain, when he is buying something at its correct price, is geneivas da’as. In other words, it is prohibited to tell someone that the item is being sold at a discount, when the purchaser is paying the actual worth of the merchandise. There is deception going on, even though there is no cheating. Notwithstanding that the buyer is not losing any money, he is still being deceived, and this is a violation of geneivas da’as.

A purchaser may also violate geneivas da’as, if he attempts to convince the seller that the item is worth less than it really is. Also, note that there might be a prohibition of ona’ah if your customer assumes the product to be higher quality than it is, and therefore, agrees to a price that is inappropriately high.


3. Here is another instance that involves geneivas da’as: someone donated money to tzedakah, specifically requesting that the money be used for a particular cause, but the money is instead diverted to a different purpose. For example, taking funds earmarked to help destitute Torah scholars and using the money for people who are not scholars or not even observant of mitzvos involves geneivas da’as (Orach Meisharim 24:7). Since this is a violation of geneivas da’as, it applies equally if the donor is non-Jewish.

However, if the use is included in the term the donor expressed when he made his donation, it is not geneivas da’as. For this reason, we can explain the famous, although possibly apocryphal, anecdote attributed to the Ponevitzer Rav. A person who was not observant made a large donation to theRav, specifying that the money be used for Torah study by students who would not be wearing yarmulkas. The Ravused the money to fund a Beis Yaakov, which certainly met the requirements as expressed by the donor, although it may not have been what he intended.

Similarly, it is said that the Klausenberger Rav, who did not accept donations for his Torah mosados from individuals who were not Shomrei Shabbos, accepted donations from non-observant individuals for his “institutions,” and used the funds for Laniado Hospital.

Mezuzah for a gentile

Rav Moshe Feinstein rules that the following case is an example of geneivas da’as: A gentile asked his Jewish landlord to place a mezuzah on the gentile’s door. Rav Moshe prohibits placing an invalid mezuzah on the door, because of geneivas da’as (Shu”t Igros Moshe, Yoreh Deah 1:184).

Giddin and gentiles

In parshas Vayishlach, the Torah teaches us the mitzvah of gid hanasheh, the prohibition of eating the sciatic nerve, which runs along and over the thigh bone. The Mishnah (Chullin 93b) states that it is permitted to send the leg portion of a shechted animal to a non-Jew with the gid hanasheh intact, because it is obvious that it is there. The Gemara is highly curious as to what the Mishnah is trying to teach. There is nothing wrong with a non-Jew eating gid hanasheh, since this is not one of the mitzvos which he is commanded. If the concern is that the non-Jew may sell the meat to a Jew who does not realize that the gid hanasheh is still there, why would a Jew be purchasing unmarked meat from a non-Jew?

After the Gemara presents several attempts to explain the Mishnah, the Gemara concludes that the Mishnah is teaching us about geneivas da’as. It is prohibited to mislead the non-Jew into thinking that you are selling him a portion of meat in which the gid hanasheh has already been removed, notwithstanding that this piece of information is basically irrelevant to him. Although the removal of the gid does not create any greater value to the non-Jew, he should not be given the impression that you sold him a product that had greater value to the Jewish seller than it really did.

Although this level of deception is not considered ona’ah (because it makes no financial difference to the purchaser), it is still prohibited as geneivas da’as, because the purchaser feels a small level of obligation, thinking that he received a product that had more value to the seller than to him, when indeed this was not true. In some future matter, he might decide to give you something to which you are not entitled, because he feels an unjustified sense of obligation to you.

Shemuel’s crossing

Once, the great amora, Shemuel, while traveling, crossed a river on a ferryboat. He asked his attendant to pay the ferry master for their fares. The attendant bartered with the ferry master, and gave him a slaughtered chicken as payment, implying that this chicken was kosher, when it was not. This act on the part of his attendant irked Shemuel, since this was an act of geneivas da’as. Notwithstanding that, to the non-Jewish ferry master, kosher and non-kosher chicken have the identical value, leading him to think that the chicken was properly kosher when it was not implies that you are giving the non-Jew something more valuable (from your perspective) than it was.

Thus, we see that giving someone an impression that you are doing him a bigger favor than you actually are violates geneivas da’as. However, we should note that most authorities contend that you violate geneivas da’as only when you say or do something that misleads the other person, but if you acted as you typically would, and there is no reason for him to think that you are misleading him, you are not in any violation.

Therefore, if the other person deceives himself, there is no violation of geneivas da’as. An example of this is when a person assumes that you attended an event specifically in his honor, but you work in that neighborhood where the event took place. Since younever said or implied that you made the trip especially for him, this is not geneivas da’as. Geneivas da’as is only if you say or do something that might lead him to such a self-deception. Therefore, it is forbidden to imply to someone that you made a special trip to attend his simcha, when, in fact, you had to be in that area anyway.

Two concerns

Geneivas da’as involves two concerns, one for the deceived party and the other for the deceiver.

It is also damaging to the individual who does the deceiving because he habituates himself to live with untruth. Of course, this affects his neshamah, and a person must train himself to live with truth.

This might be a reason why the Rambam discusses the laws of geneivas da’as in two different places: in Hilchos Dei’os (2:6), where he usually discusses how we are to develop our personalities in a Torah way, and in Hilchos Mechirah (18:1), where he discusses the laws of business honesty and ona’ah.


The Gemara mentions several instances of geneivas da’as that have nothing to do with financial matters. An example of this is begging someone repeatedly to join you for a meal, when you do not really want him to come, and you are inviting him because you know that he will turn down the invitation (Chullin 94a). This is prohibited because the invited party feels some level of obligation to reciprocate this false invitation, and it also trains the inviter to act falsely, pretending that he wants to have this guest when he does not. Similarly, it is forbidden to send someone gifts repeatedly knowing that he does not accept them. The giver wants the intended recipient to feel indebted to him, without it costing the giver anything.

At this point, let us discuss the second of our opening questions: “May I invite someone for a meal, knowing that he always declines invitations?”

If I truly want him to visit me, there is no violation of geneivas da’as. If I don’t necessarily want him to visit, I may invite him a few times to show my respect for him. However, once he has made it clear that he does not want to accept the invitation, I should invite him only if I truly want him to come. We will also see, shortly, that if I feel that people are not showing him proper respect, I may continue to invite him (even if I don’t really want him to come), if I feel that this may influence others to respect him.

The charlatan

Here are a few more examples of geneivas da’as:

Someone who acts as a big tzadik in front of people, but is, in private, not halachically meticulous (Tosafos, Bechoros 31a s.v. vechulan and s.v. ika). This display of righteousness is a form of deception (see Sotah 21b; 22b).

Implying to someone that you did something special for him when you didn’t.

Acting as if you are someone’s best buddy, but your intention is for something else. You are misleading him to think that you are his friend. In other words, where someone is אחד בפה ואחד בלב, his actions or verbal statements imply one goal, but his heart has a different goal, he is in violation of geneivas da’as (Orach Meisharim).

Why is it called geneivas da’as?

Geneivas da’as, literally, “stealing a mind,” means creating a false impression – that is, deluding a person, i.e., giving him a false perception of reality. The Gemara (Chullin 94a) rules asur lignov da’as ha’beriyos, “it is prohibited to steal someone’s mind.”

At this point, we can address the opening question: How do you ‘steal someone’s mind?’ Is that like borrowing his brains?

No, it is not. Geneivas da’as, which can literally be translated as “stealing his mind,” means to mislead or deceive him, even when the misled party is not losing anything material as a result. Simply leaving him with a wrong impression violates the prohibition.

Mistaken identity

At this point, we can begin discussing the third of our opening questions: “Someone donated money to our organization, but it is clear that she did not realize what we do. Must I bring this to her attention?”

I was once faced with this type of situation. Let me present what happened: A school that I taught in asked me to visit a gentleman who had, a few years before, made a very generous donation. After a bit of work locating him and being able to schedule an appointment with him, it was quite clear to me that he was confusing me with someone else, and that he might have been confusing the school’s program with that of another institution. In other words, there seemed to be a case of mistaken identity. Was I required to call this to his attention?

Anyone who has this question should address it to his own rav or posek. I can tell you what I did under the circumstances, which was a split-second decision without any opportunity either to research the shaylah or to discuss it with anyone.

First of all, I had not tried to deceive the potential donor. I had been supplied with accurate information that he had made a few very large donations, and that the school had tried to be in touch with him several times, unsuccessfully, in recent years. None of this involved any deception.

I presented to him many of the special, and perhaps unique, features of our institution and emphasized aspects that I thought would attract him to make another substantive donation to our cause. None of this involved any deception.

At some point in the conversation, it became clear to me that he was confusing me with someone else whom he had met previously. To this day, I do not know with whom he was confusing me, but I certainly made no attempt to create any deception.

I neither denied nor sustained his assumption that we had met before. I simply noted that he had made very significant donations in the past, and that we were hoping he would be interested in continuing the relationship.

In short, I think I handled the situation in a way that was completely honorable from a halachic perspective.

I am sure that our readers want to know if the organization actually did receive the hoped-for donation. Unfortunately, it did not.

Permission to deceive

At this point, let us discuss the last of our opening questions: “Am I ever permitted to be deceptive?”

Notwithstanding that geneivas da’as is forbidden, and it appears that most rishonim prohibit it min haTorah, there are a few instances that may appear as if they are geneivas da’as, but are permitted halachically. In other words, although they appear to be geneivas da’as, they are not.

One situation is when you do something that otherwise would be geneivas da’as, such as, you tell people that a person is a greater Torah scholar than he really is, because your goal is that others will treat him with the respect that he deserves.

Dealing in kind

There is another instance in which halacha permits someone to overlook the geneivas da’as that will result. When dealing with someone dishonest, it is permitted to act deceitfully, if it is necessary to protect yourself. For this reason, it was permitted for Shimon and Levi to deal deceitfully with Shechem.


The Gemara tells us that the great tanna, Rabbi Yehoshua, the rebbe of Rabbi Akiva, was asked: “What is the best means to become wealthy?” Rabbi Yehoshua advised that, aside from being very careful in one’s business dealings, the most important factor is to daven to He Who owns all wealth (Niddah 70b). A Jew must realize that Hashem’s Torah and His awareness and supervision of our fate is all-encompassing. Making this realization an integral part of our thinking is the true benchmark of how His kedusha influences our lives.

The true believer in Hashem and His Torah understands that every aspect of his life is directed by Hashem, and that the only procedures we follow in any part of our lives are those that the Torah sanctions.