Fast of the Firstborn
Question
What is the Fast of the Firstborn?
Answer
It is customary for firstborn males to fast on erev Pesach. The primary purpose of the fast is to recall the tenth and final plague that God inflicted upon Egypt: the death of the firstborn. (1) The fast also recalls that the firstborn were stripped of many of the rights and privileges that they were originally awarded due to their participation in the sin of the Golden Calf. The rights and privileges were then given to the Kohanim and Leviim instead.
One is to fast whether one is the firstborn of only one or both parents. (2) In some communities, firstborn females fast as well as it appears that the plague affected both the male and females firstborn (3) though common custom is not in accordance with this view. The father of a firstborn child who is not old enough to fast should observe the fast on the child’s behalf. (4) A firstborn child who was born following a miscarriage is required to fast. (5)
Ultimately, however, the Fast of the Firstborn is actually a fast that rarely takes place. This is because it has become universal custom to exempt oneself from the fast by attending a seudat mitzva . A seudat mitzva is a meal that celebrates the performance of a mitzva. For example, one who attends a brit on Erev Pesach will be exempt from the fast for having participated in the celebration. However, it is not too common for there to be a brit at multiple synagogues in a single city on Erev Pesach! As such, the custom is to arrange for a siyum , a celebration in honor of the completion of a study of Talmud, to exempt the firstborn from fasting. (6) Most congregations arrange for the rabbi or other member to prepare a siyum celebration on Erev Pesach.
In a time of great need, a firstborn who did not attend a siyum need not fast if it is too difficult to do so. So too, the fast may be waived if fasting will render performing the mitzvot of the Seder evening too difficult. (7)
Source
1. 1. Tur, OC 429, 470; OC 470:1; Mishna Berura 470:7.
2. 2. OC 470:1
3. 3. Mishna Berura 470:3. See also Shemot Rabba 18:3.
4. 4. Rema, OC 470:2.
5. 5. Mishna Berura 470:2.
6. 6. Mishna Berura 470:10
7. 7. Mishna Berura 470:2, 471:3.