It is customary for all firstborn males to fast on Erev Pesach in order to recall the tenth and final plague which God inflicted upon Egypt – the death of the firstborn. There are grounds to suggest that the Fast of the Firstborn is actually of relatively recent vintage, as it is unlikely that in the time of the Beit Hamikdash there would have been some people occupied with preparing the Korban Pesach, while others would be fasting. It might just be that the true source for the custom originates with Esther, who fasted on this day in her attempt to save the Jewish people from Haman’s plot.
It makes no difference whether one is the firstborn of only one or both parents. Some authorities suggest that firstborn females should fast as well. There is also an opinion that a firstborn delivered by caesarian section does not have to fast. It is proper for the father of a firstborn child who is not old enough to fast to observe the fast on the child’s behalf. There is a minority opinion that firstborn Kohanim and Leviim are exempt from the fast, though common custom is not like this view. A firstborn child born following a miscarriage is required to fast.
Nevertheless, the Fast of the Firstborn is actually a fast which rarely takes place. This is because it has become universal custom to exempt oneself from the fast by attending a seudat mitzva, a meal celebrating the performance of a mitzva. In fact, there is even an opinion which teaches that the institution of the Fast of the Firstborn was actually a mistake based on scribal error! Indeed, as a general rule one is actually not supposed to fast any time during the month of Nissan.
While a brit will certainly serve the role as a seudat mitzva which would exempt one from fasting, it is an option which obviously cannot be relied upon. As such, the general custom is to arrange for a “siyum”, a celebration in honor of the completion of an area of Torah study, in order to annul the fast. Most congregations ensure that the rabbi or other scholar schedule such a celebration for Erev Pesach. It is interesting to note that the common custom of exempting oneself from the fast by means of a siyum is not something which is endorsed by all halachic authorities.
There is much discussion in halachic literature regarding which areas of Torah study qualify for a siyum upon their completion. The most widespread practice is to reserve the siyum celebration for the completion of a tractate of Gemara. One may also make a siyum upon the completion of an entire order of Mishna. Some authorities even allow one to make a siyum on a single tractate of Mishna if it was studied in detail. It is also permitted to make a siyum on any book of Tanach which was studied along with the major commentaries. There is even an opinion which allows one to make a siyum on a single volume of the Zohar, even if one didn’t understand a single word of what one has read! Some authorities allow several individuals to divide the study of a tractate of Talmud among themselves and then celebrate a siyum based on their combined study. There is also an opinion that launching a book which one has written on a Torah topic qualifies for a siyum, as well.
One who has eaten at a siyum on Erev Pesach is permitted to continue to eat throughout the day. Taking food from the siyum with the intention of eating it later on or to serve it to other firstborns who did not attend the siyum is not entirely acceptable and may not exempt one from the fast. A firstborn inidivual who will be making a seudat mitzva on Erev Pesach, such as the father of a baby about to have a brit or one who will be celebrating a siyum, is permitted to eat immediately in the morning – even before the event actually takes place.
There is a minority opinion which rules that one who did not attend a siyum need not fast if doing so would prove to be too difficult. Nevertheless, in such a situation it is best to eat only light foods such as fruits, and not any foods which contain flour. Other authorities only forbid bread though they permit other foods which contain flour. One who is fasting on Erev Pesach may break his fast after midday if he is too weak to wait until the seder to eat. So too, the fast may be waived if fasting will render performing the mitzvot of the seder evening too difficult.
My next post will be Tuesday, April 13. Chag Kasher V’sameach!!
****************************************** Tur 429, 470, Mishna Berura 470:7
 O.C. 470:1. It appears that the plague of the firstborn actually affected both the males and females. Mishna Berura 470:3
 Esther Rabba 8:6, Rashi;Megilat Esther 4:17.
 O.C. 470:1
 O.C. 470:1, Avnei Derech 1:76. See also Shemot Rabba 18:3
 Kaf Hachaim 470:3
 Rema 470:2
 Piskei Teshuvot 470:2
 Mishna Berura 470:2
 Mishna Berura 470:10
 Nitei Gavriel 42:n18
 Kitzur Shulchan Aruch 107:2
 Aruch Hashulchan 470:5, Mishna Berura 470:4. See also: Magen Avraham 470:1, Chayei Adam 129:12
 B’tzel Hachachma 4:99
 Yechave Daat 1:40, Pri Hasadeh 3:91, Binyan Shlomo O.C. 59
 Igrot Moshe 1:157, 2:12, Haelef Lecha Shlomo O.C. 386
 Yabia Omer 1:26
 Kinyan Torah 5:52
 She’arim Metzuyanim B’halacha 113:10
 Yabia Omer 4:42
 Rivevot Ephraim 3:304, Piskei Teshuvot 470:6
 Mishna Berura 470:2, 471:3
 Aruch Hashulchan 470:3
 Kaf Hachaim 470:8
 Mishna Berura 470:2