The Tanach says [referring to God]:

עִם־נָבָ֖ר תִּתָּבָ֑ר וְעִם־עִקֵּ֖שׁ תִּתַּפָּֽל׃ -- With the pure You act in purity, and with the perverse You are wily. [2 Samuel 22:27 and Ps. 18:27]

Does this apply only to God or to us as well? Are we allowed to deceive someone who habitually deceives? Halacha does not allow lying, except to save a life, to keep the peace, to make people feel good, to appear humble and modest, and to protect yourself from loss or harm. Should facing a liar be added to that list?

(Note: When Rachel asks Jacob: “But is it really permitted for the righteous to be involved in deception?”, Jacob says yes and quotes that line. [Megillah 13b; also Bava Batra 123a; Ein Yaakov (Glick) on Bava Batra 8:18])

  • IIRC, we don’t infer Halochos from the books of our Prophets, but we can use them to support existing historical phenomena (see Targum).
    – Al Berko
    Nov 20, 2020 at 10:44

1 Answer 1


As a start of an answer, it is worth noting what Rav Yaakov Kamenetsky writes in Emes L'Yaakov Bereishis 27:12 in his analysis on Yaakov tricking Esav to receive the brachos, and he brings this pasuk cited above. He writes:

אלא ודאי שלפעמים מותר לאדם להשתמש בדרך הערמה כדי להשיג את מבוקשו, והיינו לפי הכלל של "ועם עקש תתפתל“ [תהלים י“ח פכ“ז], דכשהוא בא לידי התמודדות עם רמאי מסוכן מסוגו של עשו, לפעמים אין מנוס מהשימוש בדרך הערמה והשתמטות

Rather, definitely sometimes it is permitted for a person to use deceptive means to achieve what he wants, according to the principle “...With the crooked You act crookedly” (Tehillim 18:27). For example, if one is involved in daily interactions with a dangerous fraud – someone of Esav’s type – sometimes there may be no alternative other than using deceptive and evasive means.

So at least on a initial surface level it would seem from Rav Yaakov that one can deceive people like the character of Esav, namely serial deceivers and cheats.

  • Good source. What's at stake here? Why הצלת ממון is not sufficient in this case, why there should be explicit permission? On the other hand, should we jump to personal conclusions analyzing our forefathers' behavior, as in many cases it is strictly transgressive?
    – Al Berko
    Nov 20, 2020 at 10:48
  • BTW, how come "רמאי מסוכן מסוגו של עשו"? I don't recall Eisov cheating Yaakov? He cheated Eisov twice but Eisov was not responsible for his firstbornness.
    – Al Berko
    Nov 20, 2020 at 10:49
  • Who said anything about him deceiving Yaakov. Rav Kamenetsky says that someone of Esav nature - i.e. a person who constantly cheats and lies* "sometimes there may be no alternative other than using deceptive and evasive means".
    – Dov
    Nov 20, 2020 at 10:57
  • *Esav regularly tricked his father to create a false impression of his character - I can bring you numerous sources for this....
    – Dov
    Nov 20, 2020 at 10:57
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    Is he saying more than the halacha that says you may lie to protect yourself from a loss? If he is, what's to prevent you from seeking out somebody who has been convicted of defrauding, for the purpose of defrauding him? Nov 20, 2020 at 16:50

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