|Esther appeals to king Ahasveros|
The source of this practice is a passage from the Talmudic tractate Megillah(7b): Rava said: A person is obligated to drink on Purim until he does not know the difference between "cursed be Haman" and "blessed be Mordechai". The issue of whether and how Rava’s statement should be implemented in practice is a matter of disagreement between various Halachic authorities. The question, however, is not what Rava means, but whether or not the Talmud contains another opinion, contrary to Rava’s (see Ran and Baal HaMaor on Talmud, Megillah 7b; Bach and Beit Yosef on the Tur, Orach Chaim, 695). Many of the greatest Halachists follow Rava’s ruling. Maimonides writes: "What is the obligation of the [Purim] feast? That one should eat meat ... and drink wine until he is drunk and falls asleep from drunkenness" (Mishneh Torah, Laws of Megillah, 2:15).