Translation:Arukh ha-Shulchan/Orach Chaim/695
One is obligated to indulge (slightly) in the Purim feast, as it says "rejoicing and feasting".
What does the obligation (of the Purim feast entail)?: That one eats meat, and make the feast good in the way that one sees fit.
This is what the Rambam writes, and (from his language), one can infer that one is required to eat meat, because (without meat), the feast is not considered one of importance. But the rest of the food should be like a Shabbas or Yom tov (meal).
One fulfills their obligation (of feasting on Purim), by eating one meal by daytime; whereas at nightime, one is not required to indulge in their meal.
If one has their Purim feast at night, whether that is on the fourteenth or fifteenth of Adar, they do not fulfill their obligation (to have a Purim feast), as it says "days of feasting" - days but not nights.
However, one should (still) rejoice in the night time (as well), and have a small feast after one hears the megillah reading.
Even in a situation where (Purim) falls out on the night post Shabbas (Motzei Shabbas), and they are full from the Shabbas meal, it is proper to rejoice by eating a small meal.
In the Talmud (Megillah 7a), the following is taught:
- One is required to get drunk to the extent where they do not know the difference between blessed Mordechai and cursed Haman.
This is a troubling statement, because (if one reads this passage of the Talmud literally), one would be required to be nearly as drunk as Lot.
The Rambam (when writing what the law is practically) does not use this language, but (rather writes) that one should drink wine until they get drunk and fall asleep in their drunkenness. Perhaps he interpreted "until they do not know the difference" etc., because they fell asleep; which is like the Rema wrote:
- Some say one needn't get so drunk, but rather one must drink more than one is accustomed to and [then] go to sleep, and when they are asleep they do not know the difference between blessed Mordechai and cursed Haman. Both one who [drinks] more and one who [drinks] less [are acceptable,] as long as their intentions are towards Heaven.
This follows the Rambam.
But it is not understood according to this interpretation, why did the Talmud need to use such strange language: "until one does not know" etc.? It rather should have said, "One must drink until they fall asleep"!
Therefore it seems more likely that the Rambam did not intend to interpret the Talmudic passage in this manner, but rather rejected it from halakha, as the Ran wrote in the name of Rabeinu Efraim, that because of the incident related in Talmud that happened because of this, see there, it has been rejected from halakha.
However, the Tur and Shulchan Aruch wrote exactly the language of the Talmud, "until one does not know" etc., which is troubling.
Some wrote that they used to have a song ending "blessed is Mordechai, cursed is Haman"; the song was long, and when one is a little inebriated they could not recite it all.
Others interpreted it about the numerical value: it is both the same ("Arur Haman" = "Barukh Mordechai" = 502 in gematria), and one is a little inebriated they cannot figure it out.
Tosafot wrote according to the Yerushalmi: "Cursed is... cursed is Zeresh... cursed are all the wicked ones, blessed are all the righteous ones," see there. They mean that this is a little long, and when one is inebriated it is hard to recite it all [Bach].