by Rabbi Ethan Tucker
Sifra Emor Parashah 10 Perek 12:6 considers the question of whether Sefirat Haomer is to be performed during the day and concludes that, though the Korban Haomer is indeed brought during the day—the verse says “מיום הביאכם”, “from the day that you bring”—we must count at night in order to fulfill the imperative of seven “whole” weeks. By counting at night, we include the entire first day (and subsequent days) in the count and respect the wholeness of this unit. This text is cited on Bavli Menahot 66a.
Tosafot there (s.v. זכר) comment on the fact that later Babylonian Amoraim seem to have treated Sefirat Haomer as being only of rabbinic authority in the absence of the Temple and recommends therefore that one should actually try to count the Omer during twilight: 1) We need not wait until true darkness has set in, since we can treat the doubtful period of twilight leniently in the context of a rabbinic mitzvah, and 2) counting before it is truly dark will better underscore the “temimut” of each day. However, a later voice in that Tosafot rejects this reasoning.
Out of this conceptual framework emerged the idea of delaying kiddush on the first night of Shavuot until nightfall, so as not to impinge on the wholeness of the 49 days of the Omer. R. Avraham Horowitz (16th c. Poland, student of Rema) is the first to cite this practice, in the name of R. Ya’akov Falk, in his work Emek Berakhah. In this work, he explicitly defends davening early, since we see in the gemara that one can pray the Amidah for motzaei Shabbat before the end of Shabbat.
Probably bothered by the fact that the gemara also permits making havdalah before the end of Shabbat—without a candle—R. David b. Shmuel Halevi, (17th c. Poland) in his Magen David on the Shulhan Arukh, recommends delaying Arvit on the first night of Shavuot as well so that the 49 days can be completed. R. Eilyahu b. Binyamin Shapira (17th c. Bohemia, Prague) seems resistant to this extension, probably because it was not practiced in his community. It is not at all clear how widely this extension caught on in Poland either, at least right away. One can imagine that it was much more difficult to delay Arvit until nightfall than to ask people to make kiddush after nightfall once they had returned home.
There are several grounds for being lenient, however:
R. Yosef b. Pinhas Selgmann (17th c. Germany) was unhappy about this new custom, whose influence clearly had begun to make itself felt on his community. In Yosif Ometz #850 he points out that none of the great authorities in his community ever worried about this, particularly not those who would stay up to learn all night, since there would be virtually no time to have dinner and rejoicing with one’s family before beginning a serious study session. [Remember how late nightfall is in northern Europe in the middle of the summer.] He therefore says that one is certainly permitted to make kiddush after sunset, since that is already considered nighttime. He does address the question of davening late and it seems that practice had not caught on.
Degel Mahaneh Efraim rejected the entire custom, citing the Tosafot on Pesahim 99b (s.v. עד שתחשך), who seem explicitly to reveal complete lack of knowledge of such a custom.
R. Yaakov Emden (18th c. Germany) writes in his siddur that being careful about this custom is truly unnecessary, as it is based on a weak inference by later authorities and therefore even if one wants to worry about it, he can restrict his concern to kiddush, given that that was the original custom.
R. David Tzvi Hoffman prefers fulfilling the tradition of starting late but allows saying kiddush after sunset if need be, on the theory that if Sefirat Haomer is today only of rabbinic authority—as mentioned above, though the Rambam (Hilkhot Temidin U’Musafin 7:22-24) seems to disagree—then one can treat twilight leniently with respect to “temimut.” [This is indeed the position of the Ittur (Matzah Umaror 137a) and R. Nissim of Gerona with respect to other practices relating to “temimut.”]
R. Ovadiah Yosef seems to disregard the ban on early davening and is very lenient about early kiddush, particularly for those living in high latitudes.
The custom does, however, have some aesthetic advantages to it all other things being equal, and is a nice way of further encouraging attentiveness to the astronomical rhythms of the world we so often get alienated from. I see no real basis for distinguishing between Arvit and kiddush. However, if there are any obstacles to following the practice, I think the history above is sufficient to show that there are good grounds for being lenient.