The Fast of Behab
There exists a somewhat intriguing and lesser-known custom to fast on three separate days following Pesach and Sukkot. The fast is observed on a Monday, Thursday, and again on a Monday. It is called the "Behab" fast, its name being taken from combining the letters bet, hey, and bet, which refer to Monday, Thursday, and Monday, respectively. The fast is not observed immediately following Pesach and Sukkot, but rather, it is pushed off to the month which follows the holiday, being observed in Iyar and Cheshvan, respectively.[1]
The reason that the fast is delayed until the month following the holidays is because it is generally forbidden to fast during the month of Nissan, and fasting should be avoided in Tishrei, as well.[2] Some delay the Behab fasts of Cheshvan until after the 17th of the month in order to allow for the fast to be observed on the shortest days of the month.[3] It is observed on Mondays and Thursdays as these are days which are traditionally associated with both judgment and Divine favor. It was on a Monday that Moshe ascended Mount Sinai to receive the Torah and he later descended from it on a Thursday.[4]
There are a number of reasons why the Behab fast was established. Foremost, it serves to atone for any inappropriate behavior which might have taken place over the course of the recent Yom Tov.[5] This is especially true concerning inappropriate mingling with the opposite sex which might have occurred.[6] It is also serves to atone for any forbidden work which one may have performed on Chol Ha'moed.[7] Some authorities suggest that the Behab fast is actually therapeutic in nature, intended to strengthen our bodies in preparation for the changing seasons which occur following Pesach and Sukkot.[8]
The Behab fast is also an opportunity to pray that God bless the crops (appropriate following Pesach) and the rains (following Sukkot).[9] Fasting Behab also atones for the severe sin of chillul Hashem which one might have unintentionally caused at some time.[10] The extensive overeating which is prevalent on Yom Tov is also considered to be a sin which warrants having to fast Behab.[11] The Behab following Pesach also serves to atone for having possibly eaten chametz over Pesach.[12] It is interesting to note that the Behab fast following Pesach also recalls the true Fast of Esther. This is because the original Fast of Esther was actually a three day fast which took place not around Purim, but in Nissan.[13] Finally, the Behab days serve as an opportunity for general prayer, particularly that God redeem us from the Exile.[14]
The Behab fast is among those which begin at dawn and conclude at nightfall. Some individuals only observe the fast until midday.[15] It seems that this fast is only found among Ashkenazi communities as Sefardic communities never accepted it upon themselves.[16] Even among Ashkenazim the fast is not widely observed and there is legitimate basis for this. It is acknowledged that our generation is physically weaker and more pampered than previous generations, which makes fasting that much more difficult.[17] As the Fast of Behab is only a custom and is not halachically required, one should not fast if doing so will compromise one's daily productivity.[18] Those who don't fast should nevertheless curb their gastronomic pleasures on the Behab days.[19] Some have the custom to refrain from eating meat on the Behab fast days.[20]
Those who intend to participate in the fast must formally accept the fast upon themselves at the mincha prior to the fast. Alternatively, many congregations recite a "mi sheberach" in the synagogue on the Shabbat before the fast. Answering "amen" at that time with the intention to fast is deemed sufficient to be included in the fast and one need not do so again at the mincha prior.[21] One who normally fasts Behab but finds himself at a brit or other similar seudat mitzva is permitted to forgo the fast and partake in the festive meal.[22]
In the event that one of the Behab days falls out on Pesach Sheini, the fast officially takes place nonetheless, though some postpone it. Others fast only until midday in such a situation.[23] In a place where there is a minyan of individuals who are fasting, the day is treated just like all other public fast days, complete with the required insertions in the prayers and the appropriate Torah readings.[24] Kohanim who are not fasting should leave the sanctuary in order to allow others who are fasting to receive the first aliya.[25] Many congregations recite selichot prayers on the Behab days at some point during the shacharit service.[26] There is no Behab fast following Shavuot as there is little time over the course of a one-day holiday to commit any sins which would warrant establishing a fast day.[27] Nevertheless, there have been individuals in the past who fasted Behab following Shavuot, as well.[28]
[1] O.C. 492:1
[2] Tur O.C. 492, Magen Avraham 492:2, Shulchan Aruch Harav 492:2
[3] Nitei Gavriel;Pesach 43:4
[4] Tur, Beit Yosef O.C. 134, Rema O.C. 134:1, Midrash Rabba;Shoftim 5:5. See also Midrash Tanchuma;Bereishit 19:24,cited in Nitei Gavriel
[5] Tur 492, Mishna Berura 492:1, based on Iyov 1:5
[6] Tosfot;Kiddushin 81a
[7] Eliya Rabba 492:3
[8] Levush 492:1 cited in Nitei Gavriel
[9] Sefer Chassidim 227, Shach Y.D. 220:31, cited in Nitei Gavriel
[10] Tur O.C. 429
[11] Kol Bo
[12] Minhagim Maharam Mirotenberg
[13] Minhagei Eretz Yisrael (Gallis) 35:1, Minhagei Yisrael (Sperber) vol. 1 chapter 26. It is likely that Esther's three day fast was not three consecutive days either but rather somewhat like Behab.
[14] Machzor Vitri, Seder Pesach 24
[15] Cited in Nitei Gavriel;Pesach 42 note 1
[16] Kaf Hachaim 492:8
[17] Aruch Hashulchan O.C. 492:2
[18] Cited in Nitei Gavriel;Pesach 42 note 3. It seems that the Rebbes of Chabad would fast Behab, though they encouraged others not to do so.
[19] Or Zarua Tisha B'av 416
[20] Nitei Gavriel 43:13
[21] Magen Avraham 492:3, Davar B'ito;Cheshvan 3 5769
[22] Shulchan Aruch Harav O.C. 492:5
[23] Nitei Gavriel 43:11
[24] O.C. 566:2
[25] Maharik 9
[26] O.C. 566:4
[27] Beit Yosef 429
[28] Tamim De'im 177, Kol Bo Taanit 61