What is "yetzer hara"

In Judaism, yetzer hara (, for the definite "the evil inclination"), or yetzer ra (, for the indefinite "an evil inclination") refers to the congenital inclination to do evil, by violating the will of God. The term is drawn from the phrase "the imagination of the heart of man [is] evil" (Hebrew: יֵצֶר לֵב הָאָדָם רַע, yetzer lev-ha-adam ra), which occurs twice in the Hebrew Bible, at Genesis 6:5 and 8:21. The Sages of the Talmud (Berakhot 32a) have spoken about the "evil inclination" in poignant terms, making a comparison to what it is like: “To what is it like, the evil inclination in man? It is like a father who takes his small son, bathes him, douses him with perfume, combs his hair, dresses him up in his finest accoutrements, feeds him, gives him drink, places a bag of money around his neck, and then goes off and puts his son at the front door of a brothel. What can the boy do that he not sin?”

The evil inclination in man, or what is often called man's natural inclination, has been the subject of debate since time immemorial. The traditional Jewish view on this complex subject is well-defined in rabbinic literature. The yetzer hara is not a demonic force, but rather man's misuse of things the physical body needs to survive. Thus, the need for food becomes gluttony due to the yetzer hara. The need for procreation becomes sexual abuse, and so on. The idea that humans are born with a yetzer ra (physical needs that can become "evil"), but that humans don't acquire a yetzer tov ("a good inclination") until an age of maturity—12 for girls and 13 for boys—has its source in Chapter 16 of the Talmudic tractate Avot de-Rabbi Natan.