Midrash for Proverbs 1:15

Rabbi Isaac said: He [Isaac] was going to curse him [Jacob], but the Holy One, blessed be He, cautioned: "Beware, for if you curse him, you curse your own soul, for you said: 'Cursed be they who curse you' (Genesis 27:29)." Rabbi Levi said: six things serve a human - three are under one's control, and three are not under one's control. The eye, the ear and the nose are not under one's control, as one sees what is not wished for, one hears what is not desired, and one smells what is not wanted. The mouth, the hand, and the foot are under one's control. If one wishes to, one studies Torah, while if one wants to one speaks badly, and if one wants to one blasphemes and reviles. Regarding the hand, if one wishes one can offer charity, while if one wants one can rob, and if one desires one can murder. Regarding the feet, if one wishes one can go to the houses of theatre and the houses of circus, while if one wants one can go to the houses of assembly [synagogues] and the houses of study. And in the moment that one merits, the Holy One, blessed be He, makes those which one usually controls, no longer in one's control. The hand: "but the hand that [Jeroboam] stretched out against him withered" (Kings 13:4); The mouth: "now he [Jacob] must remain blessed" (Genesis 27:33); The foot: "My son, do not set out with them...for their feet run to evil" (Proverbs 1:15-6).