By Rabbi Avrohom Dovid Waxman
Time of the Seuda:
The Rema (Orach Chaim 695:2) writes that if Purim is on Friday one should eat the Seuda in the morning because of Kavod Shabbos. This is based on the halacha in Hilchos Shabbos (249:2) that it is forbidden to partake in a special meal the entire Friday so that one will have an appetite for the Seudas Shabbos. However, Rema writes that a Seudas Mitzva who’s time is on Friday is permitted. The Mishna Berurah (695:10) explains that preferably one should eat the Seudas Purim prior to Chatzos (Halachic midday). The Aruch Hashulchan (249:7) writes that one should begin before Chatzos but need not finish prior to Chatzos. Mishna Berurah adds, see what is written in Yad Efraim that quotes the Mahril. The Yad Efraim (695:2) quotes the Mahril that one may begin the Seuda until the beginning of the tenth hour of the day. This means the tenth hour of Shaos Zmanios (Halachic hours). (According to the Aruch Hasulchan ibid this means one should begin, but need not finish prior to the tenth hour.)
If one did not manage to eat a Seuda prior to the tenth hour one may still eat a Seuda. However, one should be careful not to fill himself up so that he will still have an appetite for the Seudas Shabbos. (see Rema Orach Chaim 529:1 and Mishna Berura 8). It is worth noting that Shu”t Hisorerus Teshuva (2:174) points out that one should not be Mekabel Shabbos early if one has not yet eaten the Purim Seuda. This is because one can not eat one Seuda and fulfill the obligation of Seudas Purim and Seudas Shabbos simultaneously because the Seudas Purim needs to be noticeably in honor of Purim. This is based on Shulchan Aruch (OC 688:6) based on an interpretation of a cryptic Talmud Yerushalmi (Megilah 5a) that if Shushan Purim is on Shabbos the people of Yerushalayim should eat the Seudas Purim on Sunday. As the Pasuk says (Esther 9:22) La’asos Osam Yemei Mishteh V’simcha, (to observe them as days of feasting and joy) which implies Simcha that is created by Beis Din as opposed to simcha which is created by Shamayim. Many commentaries understand this to mean that the Seudas Purim must be noticeably in honor of Purim and not in honor of Shabbos.
Pores Mapah Umikadesh:
The Meiri (Ksubos 7b) writes that when Purim is on Friday it is his custom to extend the Seuda into Shabbos and be “Pores Mapah Umikadesh,” spread a cloth and recite Kiddush. Magen Avraham (695:9) quotes the Mordechai as having done so as well. This is based on the Gemara Pesachim (100a) that if one is in middle of a meal when Shabbos begins, he should be Pores Mapah Umikadesh and continue the meal.
Shulchan Aruch (Orach Chaim 271:4) writes that if one is in middle of a meal when Shabbos begins, that one is forbidden to eat until he is Pores Mapah Umikadesh. Magen Avraham explains that one spreads a cloth over the Pas prior to reciting Kiddush. (See Pri Megadim Eishel Avraham 7 that quotes the Levush that the entire table must be covered with a cloth. The Mishna Berurah rules like the Magen Avraham.) If one was already drinking wine before Shabbos then he does not recite Borei Pri Hagafen during Kiddush.
The Marsham (Daas Torah 271:4) writes that one should wash their hands without reciting a Bracha of Al Netilas Yadayim since there is a Safek whether Kiddush was considered a Hefsek.
One must eat Pas after Kiddush to fulfill the obligation of Seudas Shabbos and Kiddush Bmakom Seuda (kiddush in the same place as the meal). One should preferably eat a bit more than a Kbaitza (the equivalent of an egg) of Pas (see Mishna Berura OC 291:2).
Shulchan Aruch (ibid) quotes a Machlokes about whether the Bracha of Hamotzi should be recited after reciting Kiddush on wine, or since Pas was already eaten earlier therefore a new Bracha is not required. The Mishna Berura (18) rules that one does not recite Hamotzi on the Pas after Kiddush since Safek Brachos Lehakel (when in doubt about Hilchos Brachos we rule leniently).
There is a Machlokes whether one is obligated to have Lechem Mishna after Kiddush since the Bracha of Hamotzi is not recited. Rav Shlomo Kluger (Shu”t Haelef Lcha Shlomo OC 113) rules that Lechem Mishna is not required. However, Aruch Hashulchan (OC 271:13) and other Poskim (see Sefer Purim Meshulash by Rav Sriah Deblitzki ZT’L 1:15) rule that one should eat from Lechem Mishna after Kiddush despite the fact that Hamotzi is not recited.
Regarding reciting Al Hanisim during Benching after being Pores Mapah, there is a Machlokes. The Pri Megadim (Mishbitzos Zahav 695:3) quotes the Taz (OC 188:6) that one should recite both R’tzeh and Al Hanisim. Shaar Hatzion (695:19) and Pri Megadim interpret Magen Avraham to agree with this as well. The Meiri (Ksuvos 7b) writes that one should recite Al Hanisim despite the fact that it is no longer the fourteenth of Adar, never the less, since the beginning of the seuda was on Purim and the Nes (miracle) of Purim occurred on the fifteenth of Adar as well, therefore Al Hanisim is still appropriate. However, the Mishna Berurah (695:15) rules like the Chayei Adam (155:32) that since reciting both appears like a contradiction, and additionally since the recitation of Al Hanisim during Benching is not so stringent (see Gemara Shabbos 24a) therefore one should only recite R’tzeh. Derech Hachaim (by the Nesivos 116:2) also rules that one does not recite Al Hanisim. (See also Ketzos Hashulchan by Rav Avraham Chaim Na’ah 47:22 that also rules this way.)
It should be noted that the Magen Avraham (Orach Chaim 271:10) writes that a Baal Nefesh (a pious person) should avoid being Pores Mapah because there are many different opinions regarding the many different Halachic issues. The Shulchan Aruch Harav (271:11) writes this as well. (It is also worth noting that the Kaf Hachaim (271:22) quotes the Arizal that based on Kabbalah it is proper to Daven Mariv prior to reciting Kiddush. See also Ma’aseh Rav 117 that quotes the Vilna Gaon that it is not proper to recite kiddush prior to Davening Mariv).
Taking a haircut and cutting nails on Purim:
Shulchan Aruch (Orach Chaim 696:1) rules that one may do Melacha on Purim. However, in a place where there is a Minhag not to do Melacha one should not do Melacha. The Rema comments that in our times the Minhag in all locations is to refrain from doing Melacha. The Rema also adds that for a Mitzva one may do Melacha.
Kaf Hachaim (Orach Chaim 696:11) quotes a Machlokes whether one may take a haircut when Purim is on Friday Lkavod Shabbos. However, from the Rema it would seem that getting a haircut and cutting nails is permitted, since there is a Mitzva to do so Lkavod Shabbos as it is written in Shulchan Aruch (Orach Chaim 260:1). The Divrei Malkiel (5:237) rules that it is permitted Lkavod Shabbos as well. The Poskim rule that therefore it would be permitted to shave Lkavod Shabbos.
Adapted by Yosef Reuven Sheinfeld from a Shiur delivered by Rabbi Avrohom Dovid Waxman, R”M at Yeshivas Mishkan Hatorah of Lakewood and author of Sefer Minchas Halevi.