Throughout Purim (night and day) there is a mitzva to be very joyful. Whatever increases one’s happiness enhances this mitzva. However, the primary expression of the mitzva is to have a festive meal (on Purim day), during which wine and other alcoholic beverages are enjoyed. It is preferable to have the meal with family or friends to make it more pleasurable.
The mitzva of joy on Purim is unique. There is a mitzva to rejoice on other holidays too (as Deuteronomy 16:14 puts it, “You shall rejoice in your festival”). That rejoicing does include drinking wine (as it makes most people happy). However, there is no mitzva to drink in large amounts. Yet, Purim’s joy is explicitly about drinking. In the phrase “feasting and joy,” the Hebrew for “feasting” is mishteh, the root of which means “to drink.” Our Sages go so far as to state that “A person is obligated to drink on Purim until he does not know the difference between ‘cursed be Haman’ and ‘blessed be Mordecai’” (Megilla 7b).
