In Judaism, yetzer hara (Hebrew: יֵצֶר הַרַע, for the definite "the evil inclination"), or yetzer ra (Hebrew: יֵצֶר רַע, for the indefinite "an evil inclination") refers to the 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 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.
Traditionally, a person's indulgence of either the good or evil impulse is seen as a matter of free choice. For example, Moshe Chaim Luzzatto wrote in Derech Hashem ("The Way of God") that "Man is the creature created for the purpose of being drawn close to God. He is placed between perfection and deficiency, with the power to earn perfection. Man must earn this perfection, however, through his own free will... Man's inclinations are therefore balanced between good (Yetzer HaTov) and evil (Yetzer HaRa), and he is not compelled toward either of them. He has the power of choice and is able to choose either side knowingly and willingly..."
Personification of evil
Although some forms of Judaism, both ancient and modern, do recognise the existence of supernatural evil, in particular fallen angels (as in the Dead Sea scrolls), the yetzer hara is often presented as a personification of evil distinct from the supernatural Satan of traditional Christianity and Islam. This tendency to demythologize Satan is found in Bava Batra and other rabbinical works, and is also found in some Enlightenment Christian writers, such as in the religious writings of Isaac Newton.
- Way of God Moshe Ḥayyim Luzzatto - 1998 "He has the power of choice, and is able to choose either side, knowingly and willingly, and possess whichever one he wishes. Man was therefore created with both a Good Urge (Yetzer HaTov) and an Evil Urge (Yetzer HaRa). "
- Dorothy M. Peters Noah traditions in the Dead Sea scrolls 2008 "Devorah Dimant, “'The Fallen Angels' in the Dead Sea Scrolls and in the Apocryphal and Pseudepigraphic Books Related to Them” (English summary of Ph.D diss., Hebrew University, 1974), 4–7. "
- Collins J Apocalypticism in the Dead Sea Scrolls 1997 "In the Book of the Watchers, the judgment on the fallen angels provides the occasion for Enoch's ascent to heaven. This is the oldest Jewish account that we have of a “round-trip” journey to heaven, where the visionary ascends to heaven "
- Bohak G. Ancient Jewish magic: a history 2008 "Magic in 1 Enoch, Jubilees, and the Dead Sea Scrolls - ... which may be dated in the third century bce, tells the story of the Fallen Angels, those “sons of God” who lusted.."
- The Jewish religion: a companion - p443 Louis Jacobs - 1995 "Very revealing of the demythologizing tendency in Rabbinic thought is the saying (Bava Batra 16a) that Satan, the yetzer hara ('evil inclination', see yetzer ha tov and yetzer hara) and the Angel of Death are one and the same. ..."
- Newton and Newtonianism: new studies 174 James E. Force, Sarah Hutton - 2004 "Newton's later expressions about the nature of Satan are for practical purposes indistinguishable from the Jewish "evil yetzer.""