“Question:
1) Do those davening alone without a minyan say Hallel in Ma’ariv on Seder night?
2) Also, when Seder night falls on Friday night, what is recited first; Hallel or “vayechulu”?
Discussion: 1) The Shulchan Aruch (Siman 487 se’if 4) tells us that Hallel is recited on the first night of Pesach b’tzibbur, with a brocho before and after Hallel. The same applies to the second night of Pesach in chutz lo’oretz. The Remo (ibid) writes that the minhag among bnei Ashkenaz is not to say Hallel b’tzibbur (i.e. in Shul during Ma’ariv) on the first two nights of Pesach. It should be noted that not all Ashkenazim follow this Remo; the minhag of both Chassidim and Perushim (who follow the Vilna Gaon) is to recite Hallel with a brocho during Ma’ariv on Seder night, as per the ruling of the Shulchan Aruch.
It should be noted that Hallel referred to here is in fact “full” Hallel, as recited during the Seder and on the first day(s) of Pesach (Shulchan Aruch Siman 488 se’if 1); unlike on the subsequent days of Pesach where only “half” Hallel is recited (Shulchan Aruch Siman 490 se’if 4).
(Rav Yechiel Michel Tuketzinski in his sefer Eretz Yisrael notes that the predominant minhag in Eretz Yisroel is to recite Hallel with brochos during Ma’ariv on Seder night; and those pious individuals who wish to follow all opinions request that the shaliach tzibbur be motze them with the brochos.)
Both the Chida (in his sefer Birkei Yosef Siman 487 s.k. 8 quoting the Rema mi’Pano) and Kaf Hachayim (Siman 487 s.k. 42) write that even an individual who is davening Ma’ariv at home without a minyan should still recite Hallel with brochos.
2) When Pesach falls on Shabbos, vayechulu is recited immediately after the Amidah, as on every other Shabbos. Unlike all other Shabbosos, the brocho of “me’ein sheva” (“mogen ovos”) is not recited on Seder night when it falls on Shabbos (Shulchan Aruch Siman 487 se’if 1). The Mishna Berura (s.k. 9) explains that this is because “me’ein sheva” was instituted because of mazikin, and Seder night is leil shimurim [therefore there is no need to recite this brocho].
The Pri Chodosh posits that in this situation vayechulu should be recited first, and then Hallel, because of the rule of todir… [i.e. the regular has precedence over the irregular] (quoted in Sha’arei Teshuva Siman 487 s.k. 2; however the Radvaz quoted by the Pri Chodosh maintains that Hallel is recited first). If the shali’ach tzibbur forgot to recite vayechulu and started saying the brocho of Hallel, the Sha’arei Teshuva (ibid) quotes an opinion that says that in this situation they should first recite Hallel and then say vayechulu (he explains that the rule of todir is “a mitzvah” and not essential; also reciting Hallel is not considered an obligation because the minhag of Ashkenazim is not to recite Hallel at all during Ma’ariv on Seder night).
Conclusion: 1) Many have the minhag to recite Hallel on the first night(s) of Pesach with a brocho in Shul during Ma’ariv. Even if one of these individuals happen to be davening at home without a minyan, should still recite Hallel with a brocho during Ma’ariv (Chidah and Kaf Hachayim).
2) When Seder night falls on Friday night, “vayechulu” is recited immediately after the amidoh (Pri Chodosh); “me’ein sheva” (“mogen ovos”) is omitted and then Hallel is recited, followed by Kadesh sholeim. If the shali’ach tzibbur forgot to recite “vayechulu” and already began the brocho of Hallel, then the tzibbur should first recite Hallel and then say vayechulu afterwards.
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