DEUT387 The ninth principle [of repentance] is breaking one's physical desire. One must impress upon himself that desire leads the soul to sin and draws transgression with cords of emptiness [Yeshayahu 5:18]. He should establish restraints for safeguarding the path to repentance--he must refrain from pleasures, and not be drawn to his own desires, even when permissible. He should follow the ways of abstinence, and only eat to satisfy his needs and to maintain his body, as the pasuk says (Mishlei 13:25), "A righteous person needs to satiate his soul." [I. e., To satisfy his needs, rather than to indulge in pleasure.] He should not engage in intercourse other than to fulfill the mitzvah of procreation or that of conjugal rights. For as long as one pursues his desires, he will be drawn towards the material [world], and he will be distanced from the path that leads to the higher intellect. Subsequently, his yetzer will prevail, as the pesukim say, (Devarim 32:15), "But Yeshurun grew fat and kicked [rebelliously]"; (ibid. this and preceding two verses) "Lest you eat and be sated... and you will become haughty"; and (Mishlei 30:9), "Lest I be sated and deny [Hashem]." The Sages, z"l, have commented (Sukkah 52b), "There is one small organ in man--when he satiates, it is hungry, and when he staves it, it find satisfaction." ... Desire, which is lodged in the heart, is the root of all of one's activities. Therefore, if he corrects his desires and all his limbs are drawn towards the intellect, subordinating themselves and serving its needs, rather than serving the desires--this will rectify all his activities, (Mishlei 21:8), "But one who is pure [I.e., free of his desires] his action is upright."