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Geneivat Da'at: The Prohibition Against Deception in Today's World
Hershey H. Friedman, PhD

Geneivat Da'at: The Prohibition Against Deception in Today's World

by Hershey H. Friedman
Professor of Business and Marketing
Department of Economics
Brooklyn College of the City University of New York

The literal meaning of geneivat da'at in Hebrew is theft of one's mind, thoughts, wisdom, or knowledge, i.e., fooling someone and thereby causing him or her to have a mistaken assumption, belief, and/or impression. Thus, the term is used in Jewish law to indicate deception, cheating, creating a false impression, and acquiring undeserved goodwill. Geneivat da'at goes beyond lying. Any words or actions that cause others to form incorrect conclusions about one's motives might be a violation of this prohibition. One does not have the right to diminish the ability of another person, Jew or Gentile, to make a fair and honest evaluation, whether in business or interpersonal relations.

Many scholars (Ritva in the name of the Baalei Tosafos, Babylonian Talmud, Chullin 94a; Rabbi Eliezer of Metz, Sefer Yereim, Chapter 224) believe that the proscription against geneivat da'at is included in the transgression of "you shalt not steal (Leviticus 19:11)." In Leviticus, the commandment against stealing is in the plural, lo tignovu (in the Ten Commandments it is in the singular, lo tignov), which enables one to broaden the law to encompass more situations. Sforno asserts that the eighth of the Ten Commandments (Exodus 20: 13), "Thou shalt not steal," while primarily referring to kidnapping, also includes stealing money and geneivat da'at. Rabbi Yonah Gerondi (Shaarei Teshuvah 3:184) regards geneivat da'at as a form of falsehood; the Torah explicitly states (Exodus 23:7) "Distance yourself from a false matter." Others, however, believe that the prohibition against geneivat da'at is not Biblical but rabbinical (Semak, 262).

The Talmudic View

The sages believed that there are seven types of thieves and, of these, the most egregious is the one who "steals the minds" of people (Tosefta Bava Kama 7:3). The Talmud (Babylonian Talmud, Chullin 94a-b) discusses the principle of geneivat da'at. "Shmuel states: It is forbidden to steal the mind of anyone, even idolaters." The Talmud then notes that Shmuel never expressly stated the above but it was deduced from an incident in which his attendant duped a heathen ferryman. There is a dispute in the Talmud as to what happened. One opinion is that Shmuel told his attendant to give the ferryman a chicken and the latter thought he was getting a kosher chicken but was actually given one that was unkosher. Another opinion is that the ferryman thought he was receiving undiluted wine but was instead given diluted wine.

Rabbi Meir (Babylonian Talmud, Chullin 94a) in further elaborating on the rules of geneivat da'at, states that a person should not urge his friend to dine with him knowing that he will refuse. One should not offer gifts to another person knowing that the latter will not accept them. One should not open a barrel of wine for someone making him believe that it was done for his honor when, in reality, the barrel was sold to a shopkeeper and was going to be opened anyway. It is permitted if he informs his guest of the arrangement. If one's oil jar is empty, one should not tell his guest to anoint himself with oil knowing that he will refuse anyway. The Talmud states, however, that in the above cases, if the purpose of the request is to show the guest honor, it is allowed. The cases cited by Rabbi Meir involve underserved goodwill. For instance, repeatedly inviting a person to a meal knowing full well that he or she will refuse results in undeserved goodwill. The invitee will believe that s/he is special in the eyes of the inviter and may even feel an obligation to reciprocate. While this is not outright theft it is inappropriate behavior for a moral individual.

The Talmud (Babylonian Talmud, Chullin 94a) also states that one should not go to a mourner's house with a bottle of wine that is only partially full. Apparently, in Talmudic times, comforters would bring bottles of wine for the mourners. An individual could easily bring a bottle that was nearly empty and strategically place it among the other bottles in a way so that the mourners would assume that the reason the bottle was empty was that people had drunk from it (see Maharsha). Nor should one fill the partially empty wine bottle with water since he deceives the mourner. This is also a case of geneivat da'at since the mourner will think he is being given a full bottle of wine. The Talmud adds that if there is a big assembly of people at the mourner's house and the comforter wants to show respect for the mourner (but cannot afford to bring a full bottle of wine), he is permitted the above deception. Again, this case demonstrates that if the purpose of the geneivat da'at is not to receive undeserved gratitude but to show honor or pay tribute to another person, it is permitted.

It is clear that geneivat da'at applies even in situations in which there is no loss of money. If geneivat da'at in buying and selling results in a financial loss, the buyer then has recourse to the courts under the laws regarding mekach taos (transactions made in error) and possibly ona'ah (overcharge). However, even if there is no financial loss and even in interpersonal situations that do not involve money, one is still prohibited from deceiving another person. The Maharsha (Babylonian Talmud, Chullin 94a) discusses the Talmudic dictum that one should not sell shoes made from the hide of an animal that died and claim that it came from an animal that was slaughtered (the latter hide is stronger). He notes that the above misrepresentation would be a problem of ona'ah (overcharging), since the hides from a slaughtered animal are of better quality and cost more than hides from animals that died. He therefore explains the Talmud as referring to a case in which the shoes were sold at a fair price. The seller, however, misrepresented the transaction and told the buyer that the shoes were made from hide that was from a slaughtered animal. There is no ona'ah because the price is reasonable; however, the seller has earned undeserved gratitude from the buyer who believes that he has received a bargain. This is why sellers are obligated to reveal any defect in a product, even if they intend to sell the product at a fair price that takes the imperfection into account.

The Talmud (Tosefta, Baba Metzia 3: 15) states that a storekeeper is not permitted to sprinkle his store with wine or oil because he "steals the minds" of people. Several commentaries (e.g., Magen Abraham, Minchas Bikurim) feel that the problem with sprinkling one's store with a superior-quality, fragrant wine is that it may fool customers into believing that all the wine sold in the store is of the same high quality. People tend to rely on their sense of smell when purchasing products such as wine or oil.

There are some exceptions to the rule prohibiting geneivat da'at. Numerous commentaries (e.g., Bach, Me'irat Einayim, Be'er Ha'Golah) indicate that there is nothing wrong with inviting someone to a meal or party that he or she cannot attend if the intent is to be polite. The prohibition is against "urging" the other party, making numerous requests to attend, and thus appearing very eager to invite him/her. Since the inviter is aware that the invitee cannot attend, repeated requests produce undeserved goodwill. Asking only once or twice, on the other hand, is the accepted protocol and will not be misinterpreted by the invitee. Indeed, not asking someone to come to a party could result in hurt feelings; others may think the person was not invited because he is an unworthy individual.

The Talmud (Babylonian Talmud, Chullin 94b) indicates that geneivat da'at may not be an issue if an individual has deceived himself. Mar Zutra b. Nachman was traveling from the town of Sikara to Mahuza at the same time that Rava and Rabbi Safra were going to Mahuza. They met and Mar Zutra assumed that the two sages had come specifically to meet him, so he told them that they should not have gone to the trouble. Rabbi Safra felt obliged to explain to Mar Zutra that he had not known of his arrival, but had he known, he would have done even more. Rava, however, thought that this disclaimer was not necessary since Mar Zutra had deceived himself. Tosafos (Babylonian Talmud, Chullin 94b) makes a distinction between this case and the above case with the barrel of wine that was sold to a shopkeeper and was thus not being opened specifically for the guest. In the case of the barrel of wine, the logical expectation is that the barrel of wine is being opened for the guest. This is why the mistaken assumption has to be corrected. In the case of Mar Zutra, there is no reason to assume when encountering people traveling on a road that they have come to greet you. Thus, one is not obligated to correct the misimpression. Levine (2000, pp. 21-22, 38-39, 120-121) uses the logic of the hypothetical "reasonable man" and states (p. 120): "the seller's disclosure obligation consists not only of a duty not to mislead in an affirmative manner but also of a requirement to disabuse the customer of his reasonable misperception about the product." The obligation is to correct sensible and logical misunderstandings, not errors that reasonable and sensible people would not make.

The Shulchan Aruch

The Shulchan Aruch, written by Rabbi Yosef Caro, is accepted throughout the Jewish world as the authoritative work on halacha (Jewish law). It was completed in the middle of the 16th Century and means "set table." It lives up to its name and is easy-to-read, concise, and to the point. It is based to a large degree on Maimonides' classic legal code known as Mishneh Torah ("a repetition of the Torah"), which was completed between 1170 and 1180 CE. The Shulchan Aruch and the Mishneh Torah are two of the best-known Jewish legal codes.

The Shulchan Aruch (Choshen Mishpat, 228: 6) states that one is not allowed to fool others in buying and selling or to "steal their minds." Thus, if there is a defect in merchandise, the seller is obligated to inform the buyer, even if the buyer is an idolater. One is also not permitted to sell meat of an animal that died (and is therefore not kosher) to an idolater and misrepresent it as ritually slaughtered meat and thus kosher. Although the idolater has not suffered any financial loss, he believes that the Jew cares for him by selling him meat that is permissible to Jews. This results in undeserved gratitude. The Shulchan Aruch then adds that one is not permitted to "steal the mind" of others with words (geneivat da'at b'dvarim) and make it appear as though he is doing something on his fellow's behalf if he does not intend to do it. Examples of this include the above-cited cases discussed by Rabbi Meir dealing with undeserved gratitude/goodwill (e.g., inviting someone to a feast, offering a gift to someone who will refuse it, and opening a barrel of wine). Maimonides also discusses geneivat da'at in the area of transactions (Mishneh Torah, Hilchot Mechirah 18:1) and in interpersonal relations (Mishneh Torah, Hilchot De'ot 2:6). As noted above, geneivat da'at has ramifications in both business transactions and personal interactions (e.g., insincere invitations).

The Shulchan Aruch (Choshen Mishpat, 228: 6-7) notes that the proscription against geneivat da'at does not apply in two situations: (1) If an individual should have realized that something was not necessarily being done for his benefit (as in the case involving Mar Zutra and the two sages) but mistakenly believed so, then one is not obligated to inform him of his erroneous assumption. (2) If one offers someone something knowing that he will refuse not because he seeks undeserved gratitude but because he wants to show honor and respect for the other party, then it is permitted.

Situations involving Geneivat Da'at

The following are some situations that may involve geneivat da'at. The purpose of this paper is not to arrive at definitive halachic (Jewish law) conclusions but to make the public aware of the issues involving geneivat da'at. Those who desire to know the final halacha should consult with a halachic authority.

Deceptive Offers: Urging someone to come to a meal knowing that s/he will not come; offering a person a gift knowing that he will not accept it; and opening a barrel of wine that one had to open anyway and make guests believe that it was opened strictly for them. These cases are directly from the Talmud (Babylonian Talmud, Chullin 94a). Modern versions of the above might include offering a person a lift home from a party knowing that she arrived with her own car and does not need a lift. Sending a wedding or bar mitzvah invitation to an individual that you know will not or cannot come should not be a problem if you are doing it to show respect to the invitee. Also, inviting someone to a party or wedding in order that his or her feelings are not hurt would be permissible. As noted above, the problem is with "urging" (i.e., making repeated requests) someone to come. Sending an invitation is also considered proper etiquette even if the inviter knows the invitee cannot make it. If, however, the invitation is sent for one's own benefit, e.g., to receive a gift, and the reality is that one does not want the person to come, there may be a problem of geneivat da'at. Making a gift appear much more valuable than it really is would also be prohibited by Jewish law (Basri 1982, p. 245).

Irregular Merchandise: Sellers are obligated to disclose any defects, deficiencies, shortcomings, or imperfections in their merchandise; otherwise, they are guilty of geneivat da'at. This is true even if the product is being sold at a fair price so that there is no problem of mekach taos. Tamari (1991, pp. 73-76) stresses that Jewish law rejects the concept of "Let the buyer beware;" the burden of ensuring that the buyer is not deceived is on the seller.

Deceptive Quality/Advertising Puffery: Misleading one's customers into thinking that the quality of the item they purchased is much better than it really is would be geneivat da'at. This case is similar to the Talmudic case (Babylonian Talmud, Chullin 94a) involving selling shoes made from the hide of a dead animal and misrepresenting them as coming from the hide of a slaughtered animal. Deceptive advertising would be one way of dishonestly raising customers' expectations regarding the quality of products. Selling products with misleading nutritional information, e.g., selling nutrition supplements as weight-loss, wrinkle-elimination, or memory-improvement aids when there is no evidence that they have any such beneficial effect, would also fall under the prohibition of geneivat da'at.

Spitz (1997) states that if individuals believe that the quality of a product manufactured in one place or country (e.g., Swiss watches, Japanese cameras) is superior to that of competing brands made elsewhere, then sellers are not permitted to suggest or hint that the merchandise comes from the area with the reputation for superior quality if this is not the case. Levine (1987, pp. 51-57) asserts that advertising puffery may also result in geneivat da'at and thus be prohibited by Jewish law. Puffery is exaggerated, overstated advertising; the kind on which reasonable consumers will generally not rely. Puffery might include very vague and/or subjective statements regarding product superiority, e.g., "best in the universe," "whiter than white," or "fit for an emperor." True puffery is not usually regarded as deceptive advertising. Levine, however, believes that if the puffery produces expectations on the part of the consumer that the product cannot deliver, then it would be considered geneivat da'at. Tamari (1996, p. 74) feels that deceptive packaging that makes customers believe that they are receiving larger or more items may also constitute geneivat da'at.

Levine (2000, pp. 60 -61) discusses a comparative advertisement for Baby Orajel, a product that helps alleviate the pain of teething babies that notes that the product works within one minute, whereas Children's Tylenol takes up to 30 minutes to take effect. The advertisement states: "If you're giving your baby Children's Tylenol, your baby could wind up suffering up to thirty minutes longer than necessary." What the advertisement does not state is that Baby Orajel wears off much sooner than Tylenol. This, according to Levine, constitutes geneivat da'at.

Deceptive Bargains: Deceiving one's customers and making them believe that they have received a bargain when they have not would also be geneivat da'at. Thus, phony markdowns, i.e., marking an item with a spurious high price solely for the purpose of slashing it and thus make customers think they are getting a bargain is prohibited. In addition, falsely claiming "last day of sale" would also be forbidden [Tamari (1996), p. 74].

Levine (1987, p. 48) states that firms that find that they are stuck with a product that is not selling well and therefore have to reduce the price to eliminate the excess inventory are not permitted to promote the sale as a discount sale and thereby suggest that customers are obtaining a bargain. Since, in reality, the price discount is due to declining demand, the new price represents a "fair" price, not a bargain price, and the firm should call the "sale" a clearance sale. Otherwise, the firm would acquire undeserved goodwill. Tamari (1991, pp. 75-76) notes that advertisements claiming sale prices that are in actuality not lower than the regular price are geneivat da'at. Kaufman (2002, p. 39) prohibits a firm from running advertisements that state "Watches normally $39.99, now only $19.99" if the $39.99 price is simply the manufacturer's suggested selling price, not the usual selling price for these watches. Spitz (2001) maintains that retailers may not claim the following if they are untrue: "I can give it to you for $50, but not less, because that's what I myself paid for it"; "This is the best model of its kind"; and "the cheapest prices in town." It is clear from the above opinions that a seller is not permitted to make a buyer believe that she has obtained a bargain when the reality is that she has paid the regular price. Even causing a customer to believe that they have received an "exceptional bargain" when all they have gotten is a small bargain would be problematic.

Deceptive Credentials/ Cheating on Examinations: Cheating on examinations is definitely a violation of geneivat da'at. Both the teacher of the course and future employers who rely on grades to determine the abilities of potential employees have been deceived. Rabbi Moshe Feinstein (Igros Moshe, Choshen Mishpat 2: 30) and Rabbi Menashe Klein (Mishna Halacha 7: 275) make it clear that cheating on tests given in secular studies is prohibited. Additional information on this subject may be found at Povarsky (1995) and Resnicoff (2002).

Similar to the problem of cheating on examinations, is the question of the permissibility of changing the details of cases discussed in a medical paper to make the article more publishable and thus improve one's chances of getting a job. In various fields such as academe, a resume containing several publications is more likely to lead to a job than one with few publications. Rabbi Waldenberg (Tsits Eliezer, vol. 15, no. 12) felt that this also falls under the prohibition of geneivat da'at. It is interesting to note that Nuovo (2002) recently published a paper that discussed the problem of the use of statistics in medical studies to make new drugs sound much more effective than the reality.

Levine (2000, p. 330) indicates that "creating a false impression for the purpose of counteracting an unwarranted bias" may be permitted under some circumstances. Thus, one may be permitted to dye his beard to make himself or herself appear younger and thereby get a job. This, however, is only permitted if the individual is young enough to perform the required work. Suppose the work involves, say, heavy lifting that is more appropriate for a much younger person, then dying one's hair and beard to appear youthful would not be permissible.

Deceptive Testimonials: Product testimonials and endorsements may be problematic according to Levine (1987, pp. 57-59). Since in most cases experts and testing laboratories that endorse products are paid for their services, they are not unbiased. If the public believes that their opinions are truly objective and impartial, the endorsement will constitute geneivat da'at.

Deceptive Accounting Practices: Accountants or auditors who purposely provide deceptive financial statements are guilty of geneivat da'at (Tamari (1995), pp. 65-66). Needless to say, the recent scandals involving Enron, Global Crossing, Tyco, WorldCom, Adelphia Communications, Rite Aid, and several other firms demonstrate how easy it is for auditors to use creative accounting to distort the true financial situation of a company and deceive the public. Friedman (2002) notes that dishonest auditors are also guilty of lifnei iver, placing a "stumbling block before a blind person."

Deception for Charity: If an individual, even an idolater, requests that his or her contribution be given to a specific charity, switching to another charity without the consent of the donor would be geneivat da'at (Rashi, Babylonian Talmud, Baba Bathra 11a).

In many synagogues the custom is to auction off various honors, e.g., being called up to the Torah, and the proceeds usually go to the synagogue. Suppose one knows that an individual will pay anything to get a particular honor, say, getting called up to the Torah on Yom Kippur, is it permissible to bid against the individual in order to drive up the price and thus benefit the synagogue? This question is discussed in Sheilot U'Teshuvot Yosef Ometz (Section 57) and in the case discussed there is an additional factor. The shill has agreed that if he wins the bidding war, that he will only have to pay a fraction of what he bid. According to Yosef Ometz, this is prohibited and is geneivat da'at. First, if the shill wins the bidding war and obtains the honor, the other members of the synagogue will think he donated a great deal to the synagogue for the honor when the reality is that he contributed considerably less. Second, even if the shill loses the bidding war, the members of the congregation will think that he was willing to donate a considerable amount, when, in reality, he had no interest in giving that large an amount to the synagogue.


Certainly, we all should strive to be as straightforward and honest as possible in all our dealings, not only business. Indeed, the Talmud (Jerusalem Talmud, Makkot 2:6) declares that if an individual is knowledgeable in one tractate of the Talmud and he goes to another town in which people want to provide him with honor because they believe that he knows two tractates, he is required to correct their false impression. This seems to contradict the Babylonian Talmud (Chullin 94b) that indicates that if people have fooled themselves, one is not obligated to correct the misperception. However, in this case it is not unreasonable to expect that one who has expertise in one tractate also has proficiency in another since many of the tractates of the Talmud are interrelated, interconnected, and overlapping (Levine 2000, p. 120-121). In addition, the individual is actually being honored for his accomplishments in two tractates and his participation strengthens this false belief (Spitz, 1997). The prohibition against geneivat da'at, as noted above, goes beyond simply requiring that one not deceive. Individuals must correct false impressions that have been made by other people making reasonable assumptions as to one's motives both in business and non-business situations.

Geneivat da'at is not a minor prohibition. Rabbi Eliezer of Metz (Sefer Yereim 224) says that Abshalom, son of King David, deserved death for violating the Torah law against geneivat da'at. As the Talmud notes (Babylonian Talmud, Sotah 9b), Absalom "stole the hearts" (Rabbi Metz clearly believes that "stealing the heart" is the same as geneivat da'at) of three parties - his father, the court, and the people of Israel - and therefore was punished in that his heart was pierced by three darts (II Samuel 18: 14).


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