Variantly: (Devarim 11:16) "Take heed unto yourselves lest your hearts be enticed": He said to them: Take care that the evil inclination not lead you astray to separate yourselves from the Torah. For once a man separates himself from the Torah, he cleaves to idolatry, as it is written (Shemoth 32:8) "They have turned aside quickly from the way which I have commanded them; they have made for themselves a golden calf."
And it is written (I Samuel 26:19) "If the L-rd has stirred you up against me, let Him accept an offering. And if the sons of man, let them be cursed before the L-rd. For they have driven me out this day from joining the inheritance of the L-rd, saying 'Go and serve other gods.'" Now would it enter your mind that David, king of Israel, would serve idolatry? (The thought is,) rather, that his ceasing to occupy himself with words of Torah is equivalent to his cleaving to idolatry.