While it goes without saying that telling an outright lie is forbidden, even passive lying – omitting the entire truth or otherwise misleading someone – is forbidden. This is known as geneivat da’at, which means “stealing another person’s thoughts.” The principles of geneivat da’at teach that one must be honest and always speak in a manner that reflects one’s true thoughts and intentions. This applies to all human beings, whether Jewish or gentile.1 Our Sages teach that geneivat da’at is the worst form of theft that exists2 and is far worse than stealing property.3 We are taught that G-d hates those who deceive others.4
Geneivat da’at includes all forms of giving mistaken impressions and allowing for false assumptions.5 Frequently cited examples of this are extending an invitation for a meal to someone who will certainly refuse or who is otherwise unable to attend, offering a gift knowing that it will be refused, and a storekeeper misleading customers by altering the appearance of his merchandise in order to make it appear more valuable than it truly is.6 It is even forbidden to sell a gentile non-kosher meat if he believes that he is buying kosher meat. This is true even though a gentile is permitted to eat non-kosher meat.7 Similarly, in the event that one must dispose of non-kosher food and one chooses to do so by giving it to a gentile, one may not allow the gentile to believe that he is receiving a gift. He must be told that the reason he is receiving the food is because it is not kosher and therefore one has no use for it.8
Students and others taking tests are forbidden to copy answers off another person’s paper.9 In fact, the halachic authorities express shock at the widespread disregard for cheating on tests, deeming it a sin equal to all others in the realm of lying, stealing, and cheating.10 Lying on Shabbat is considered to be an exceptionally severe sin.11 When engaged in business negotiations, one is not permitted to falsely claim that one has another potential buyer in order to intimidate the current negotiator into accepting one’s conditions.12 It is forbidden to make oneself look younger than one really is for a date, job, or other age-restricted pursuit.13 One must also not allow others to believe that one is a bigger scholar than one really is.14
Closely related to the concept of geneivat da’at is giving credit where credit is due. The Talmud teaches that whoever reports something in the name of the one who said it brings redemption to the world.15 The source for this is the Megillat Esther, where it says, “And Esther told the king in the name of Mordechai.”16 It is explained that as a result of Esther crediting Mordechai with the information that put an end to the plot to assassinate King Achashverosh, the Jews were later saved from Haman’s plot.
It is considered tantamount to theft, as well as a number of other prohibitions, to withhold the source of one’s knowledge, especially Torah knowledge.17 Our Sages label one who is remiss in giving credit to the sources of one’s knowledge and information as “one who wraps himself in a tallit that does not belong to him.”18 In the event that a particular teaching was transmitted via a number of people, one need only quote the first and last source of the teaching.19 One is not required to quote the source of a teaching if one’s intention in quoting it is to disprove it or otherwise argue against it.20 So too, if the one who originated the teaching wishes to remain anonymous, there is no requirement to cite him. It is especially important to quote in the name of a person who is deceased, as doing so is said to bring that person pleasure in heaven.21 If one is unsure where a certain teaching originated from, one is permitted to make up the name of a great rabbi if doing so is necessary to convince others to accept it.22
It is forbidden to mislead someone into thinking that he is getting a great deal when he really isn’t.23 The Talmud24 tells the story of Rabbi Safra, who was in the middle of praying when a person entered his store and wished to purchase a certain item. The man offered Rabbi Safra a precise amount of money for the item, but as Rabbi Safra was in the midst of praying, he didn’t answer. The customer, thinking he was being ignored due to the price he had offered, continued to raise the amount of money he was willing to pay in order to purchase the item. Eventually, when Rabbi Safra had finished his prayer, he told the buyer that he would sell the item for the price that was first offered, as in his heart he really had accepted that first, lower offer.
Although we are unlikely to reach the spiritual heights of Rabbi Safra, make no mistake: exaggerating, misleading, tricking, deceiving, and giving people false impressions all spring from terrible character traits and are forbidden. Telling the boss that you are late for work due to a nonexistent traffic jam falls perfectly into this category. Admit that you were late and that you will try harder next time! We are taught that one who always speaks the truth will merit having all his wishes fulfilled.25
- Rambam, Hilchot Deot 2:6; Rambam, Hilchot Mechira 18:1; Sefer Chassidim 51.
- Tosefta, Bava Kamma 7:3; Sha’arei Teshuva 3:184.
- Bava Metzia 58b.
- Pesachim 113b.
- Chullin 94a; Rambam, Hilchot Deot 2:6.
- Chullin 94a, CM 228:6; Sma, CM 228:7, 8; Kitzur Shulchan Aruch 63:5; Sefer Chassidim 51.
- Rambam, Hilchot Deot 2:6; Rambam, Hilchot Mechira 18:3; CM 228:6, 9; Sha’arei Teshuva, OC 645:6.
- Meiri, Chullin 94.
- Mishneh Halachot 7:275; Igrot Moshe, CM 2:30.
- Shevet Halevi 10:163.
- Yerushalmi Demai 4.
- Teshuvot V’hanhagot 4:216.
- Sefer Chassidim 379.
- Yerushalmi Makkot 2:6.
- Megilla 15a; Avot 6:6.
- Esther 2:22.
- Sha’arei Teshuva, OC 156:2; Sefer Chassidim 586.
- Shach, YD 242:43.
- Piskei Teshuvot 156:27.
- Sha’arei Halacha U’minhag (Chabad), OC 102.
- Sefer Chassidim 224.
- Eruvin 51a; Pesachim 112a. See Piskei Teshuvot 156:28.
- Bava Metzia 60a.
- Makkot 24a.
- Elya Rabba 155:2.