Maimonides teaches that “The reading of Megillat Esther supersedes all other commandments.”
Megillat Esther tells the story of the deliverance of the Jews in ancient Persia from Haman’s plot “to destroy, kill and annihilate all the Jews, young and old, infants and women, in a single day.”
The Talmud says that one is obliged on Purim to drink until he can no longer distinguish between “Cursed is Haman” and “Blessed is Mordechai.”
The Talmud continues relating how Rabbah ben Nachmani and R. Zeira became very drunk on Purim and that the former cut the latter’s throat.
The next day, Rabbah prayed on R. Zeira’s behalf and brought him back to life.
A year later, Rabbah asked, “Would you like to celebrate Purim with me again this year?”
“One cannot count on a miracle every time,” R. Zeira replied.
According to Midrash Mishlei, in the days of the Messiah, when all the holidays and festivals will be forgotten, Purim will still be celebrated.
