LEV399 Concerning the giving of advice, we have been taught in Toras Kohanim (Kedoshim 2:14): "'Do not place an obstacle before a blind man' [this verse] [and this refers] to one who is blind in this matter.… When a person is approached for advice, whether regarding something that he takes a personal interest in or something that does not relate to him at all, he is obligated to adhere to pristine truth [and to present it] with clarity. The Torah knows very well how swindlers operate, and we are not dealing with fools whose harmful advice is well-known and obvious, but with clever people who are wicked, who give advice that appears to be truly beneficial but in actuality is not in the other party's interest to his detriment – and for the benefit of the one who is giving the advice. Because [of this concern] they said: "Although you might say,' I am giving him good advice,' this is something that is known only to you.…" How many times do people fail in these transgressions daily as their lust for profit lures them onward? In Scripture the severity of their punishment has already been spelled out (Devarim 27:18): "Cursed is he who misleads an undiscerning person." By contrast, the responsibility of an honest person is such that when someone comes to him for advice he must give him the same advice that he would himself follow, having no other end in mind, immediate or distant, than the benefit of the one who has come for the advice. And if it should happen that he sees himself as standing to lose by such advice, he should reveal this to the other party if he is able to, and if he cannot, he should excuse himself and not give any advice. Either way he should not offer advice whose end result will not be beneficial for the one who is seeking advice, unless that person is ill-meaning in his intent. In that case it is certainly a mitzvah to deceive him, and it has already been stated (Tehillim 18:27): "And with the crooked be cunning," and [the episode of] Chushai Ha'arki demonstrates this (see Shmuel II 17:5-14).