Chapter 5. Laws of Shavuot That Falls on Saturday Night

[The coming years in which the festival of Shavuot will fall on Saturday night are: 5789, 5792, 5796, 5799, 5802, 5803, 5806, 5809, 5816, 5819, 5823, 5826, 5829]. For the laws of Yaknehaz in these years, see the laws of Yaknehaz.

Haircuts at the End of the Days of Sefirat HaOmer for Those Who Follow the Opinion of the Arizal
32. Even for those who follow the Arizal’s custom not to take a haircut until the night of the 49th day of the Omer, when the festival of Shavuot falls on Sunday, one may take a haircut from Friday night. [1]

Immersion in Honor of Yom Tov
33. When the eve of Shavuot falls on Shabbat, one should immerse in honor of Yom Tov on Friday.

Seudah Shelishit
34. It is a mitzvah to eat seudah shelishit before the tenth hour [and ideally one should pray Minchah before seudah shelishit]. However, if one did not manage to eat before the tenth hour, he should eat after the tenth hour, but then he should not eat the measure of a fixed meal, meaning as he normally would on a weekday; rather, it is a mitzvah to eat only
slightly more than a kebeitzah of bread, so that he will eat at night with an appetite. [2]

Sleeping on Shabbat, the Eve of Shavuot
35. There is room for doubt whether it is permitted for a person who is going to sleep during the day on Shabbat to say that he is going to sleep so that he will have strength to stay awake at night. [3]

Preparing from Shabbat for Yom Tov
36. It is forbidden to prepare from Shabbat for Yom Tov, even things that are not melachah but are merely in the category of exertion. Therefore, one should not set the holiday table on Shabbat, nor should one roll the Torah scroll on Shabbat to the reading for Shavuot. [4]

Taking Food Out of the Freezer on Shabbat for Yom Tov
37. One may not take cooked food or challot out of the freezer on Shabbat for Yom Tov until tzeit hakochavim and reciting “Baruch HaMavdil bein kodesh lekodesh”; however, in a pressing situation one may take them out while it is still well before the end of the day. [5]

[1] See above, the laws of Sefirat HaOmer; Kaf HaChaim (siman 493, se’if katan 13); and this is also explained in Pri Etz Chaim, that this was the practice of the Arizal.
[2] Rema (siman 529, se’if 1), Biur Halachah (there, s.v. “miminchah”), Sha’ar HaTziyun (se’if katan 9), and see further Mishnah Berurah (siman 291, se’if katan 17), Biur Halachah (there, s.v. “achar sheyitpalel”), Mishnah Berurah (siman 529, se’if katan 8), and Sha’ar HaTziyun (se’if katan 10).
[3] See Mishnah Berurah (siman 290, se’if katan 4).
[4] Mishnah Berurah (siman 667, se’if katan 5).
[5] Ibid.