A verse in Megillat Ester teaches that Purim is to be observed as "Yemeh Mishteh Ve’simha" – "days of feasting and rejoicing." The word "Mishteh" indicates that one must have a festive meal on Purim. Although the word "Mishteh" literally means "drinking," this term is understood as referring also to eating, but the meal is called a "Mishteh" because the drinking constitutes the primary component of the feast.
The Gemara inferred from the word "Yemeh" ("days") in this verse that the Misva of Se’udat Purim (the Purim feast) can be fulfilled only on Purim day. One does not satisfy the obligation by having a meal on the night of Purim. The Poskim say that it is proper to have a meal on the night of Purim in honor of the festive occasion, but the strict requirement of Se’udat Purim is fulfilled only on Purim day. (Of course, we in any event generally eat a meal on the night of Purim, because the day before Purim is observed as a fast day.)
One satisfies the obligation of Se’udat Purim anytime during the day of Purim, even if he did not begin his meal until just before sundown. Preferably, though, most of the meal should take place during the day, before sundown. At very least, one should ensure to eat the first Ke’zayit of bread before sunset.
According to some, including the Shala Ha’kadosh (Rav Yeshaya Horowitz, d. 1630) and the Rashash (Rav Shalom Sharabi, Yemen-Jerusalem, 1720-1777), the Purim meal should preferably be eaten in the morning of Purim. This is, indeed, the practice among Kabbalists, and this was also the custom of Hacham Ovadia Yosef – to eat the Purim meal in the morning, after fulfilling the other Misvot of the day (prayers and Megilla reading, Mishloah Manot, and Matanot La’ebyonim).
The more prevalent practice, however, is to eat the Se’udat Purim in the afternoon. This is due mainly to pragmatic concerns, as people are very busy in the morning delivering their Mishloah Manot and Matanot La’ebyonim, and preparing for the meal, and some travel for the meal or have guests who need to travel to them. Those who eat the Se’udat Purim in the afternoon must ensure to first recite Minha before the meal. Once the time for Minha arrives, it is forbidden to sit down to a large meal before reciting Minha, and thus one who eats the Purim meal in the afternoon should first recite Minha. Hacham Bension Abba Shaul (Israel, 1924-1998) ruled that even if one will need to recite Minha privately, without a Minyan, if he prays before his meal, he should nevertheless do so, as one may not begin a large meal in the afternoon before reciting Minha.
The question arises as to when one should conduct the Purim feast when Purim falls on Friday (as it does this year, 5781/2021). Halacha requires starting Shabbat with an appetite, so we can enjoy the Friday night meal and thereby properly respect Shabbat. Accordingly, the Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933) cites (in Siman 695) those who maintain that when Purim falls on Friday, one should have the Purim meal in the morning. Even those who generally have the Purim meal in the afternoon should do so in the morning when Purim is celebrated on Friday, in order to ensure that one begins Shabbat with an appetite.
If, however, this cannot be done, because of everything one needs to do on Purim morning, then the meal may be eaten in the afternoon, after Hasot (halachic midday). The Rama (Rav Moshe Isserles of Cracow, 1530-1572) rules that it is permissible to eat a large meal on Ereb Shabbat if the meal constitutes a Se’udat Misva (a meal which fulfills a Misva), and thus the Purim meal, which clearly fulfills a Misva, is allowed on Friday afternoon. It should be reiterated that one must recite Minha before eating the Purim meal Friday afternoon.
Of course, if one eats the Purim meal on Friday afternoon, he should endeavor to eat early in the afternoon, so that he will have an appetite Friday night. If he cannot, then he should try to eat the meal no later than the beginning of the tenth Halachic hour of the day. (This time of year, in the New York area, this point is approximately 3pm.) But if one is unable even to eat before the tenth hour, then he may eat even later, until sundown.
Preferably, the Purim feast should include meat. One who cannot eat meat for health reasons can eat poultry, instead. Hacham Bension Abba Shaul writes that although there is no strict requirement to include bread in the Se’udat Purim, one should preferably include bread.
After the meal, one must make every effort to remember to include "Al Ha’nissim" in Birkat Ha’mazon. There is a debate among the Poskim as to whether one must repeat Birkat Ha’mazon if he forgot to include "Al Ha’nissim," and although Halacha follows the opinion that Birkat Ha’mazon is not repeated in such a case, one should make an effort to avoid this situation.
Different customs exist as to the extent to which one should drink wine on Purim, and each community should follow its Rabbi’s guidance. According to all opinions, however, drinking on Purim must not lead to frivolity, inappropriate behavior, or the neglect of even a single Misva. If, as a result of drinking on Purim, one conducts himself or speaks in an inappropriate manner, or misses a single prayer or Beracha, then "Yasa Secharo Be’hefsedo" – any reward he might have received for the Misva of celebrating on Purim is offset by what he has lost.
It is worth noting in this context the custom we have to recite during the Minha prayer on Shabbat afternoon the verse, "Va’ani Tefilati Lecha Hashem Et Rason…" – "And me, this is my prayer to You, G-d, at this time of acceptance…" Shabbat afternoon is an "Et Rason" ("time of acceptance"), an occasion especially suited for the acceptance of our requests. The commentaries explain that on Shabbat afternoon, after we eat, drink and rest, when we return to the synagogue to pray and learn Torah, we earn Hashem’s favor. He sees the difference between us and other peoples, who, on their day of rest, eat and drink and then engage in meaningless or sinful behavior, whereas we use our day of rest for sacred pursuits. This concept should inform our attitude towards the Purim celebration, as well. The festivity of Purim is meaningful when it elevates us to higher levels of Kedusha, and loses its value if, G-d forbid, it does the opposite.
Summary: While some have the custom to conduct the Purim meal in the morning, the more common practice is to eat the meal in the afternoon. Those who eat the meal in the afternoon must recite Minha before beginning the meal. However, when Purim falls on Ereb Shabbat, it is preferable to eat the meal in the morning, before Hasot (halachic midday). If this is not possible, the meal should be eaten in the early afternoon hours (after first praying Minha). If even this is not possible, then the meal should be eaten before the tenth hour of the day. if one cannot eat before the tenth hour, then he can eat even later, until sundown.
