Pesach - Taanit Bechorim

Taanit Bechorim

On Taanit Bechorim, all firstborn males should fast whether firstborn to their father or their mother. According to many poskim, even one born through Caesarian section should fast [Chok Yaakov 470:2], although some rule leniently [Kaf HaChayyim 470:3]. There is even an opinion that a mother would fast for her son if he is under bar mitzvah and the father is a bechor himself [Orech Chaim 470:2].

If a woman’s first pregnancy ended in a miscarriage or a stillborn child, the first baby born to her afterward, if male, would be considered a firstborn and have to fast. If a couple has a firstborn son who is not yet Bar Mitzvah age but is at least 30 days old, it is customary for his father to fast on his behalf.

A distinguishing feature of this fast is that it does not have a Talmudic source and is classified as a minhag (custom) rather than a law. 

For this reason, if on Erev Passover a first-born attends a seudat mitzvah, such as a brit, pidyon haben, or siyum, he would be permitted to partake of the seudah and be exempt from fasting for the rest of the day. 

As a result, it has become common practice for individuals to conduct a siyum on Erev Passover after shacharit so that all attending firstborn males, as well as fathers of firstborn males who are not yet bar mitzvah age, can avoid the need to fast.

If a firstborn is unable to participate in a siyum on Erev Passover, many poskim permit listening to a siyum over the phone [Rav Hershel Schachter, Teshuva dated 28 Adar 5780 p. 2], and he knows that fasting the entire day will severely impact his ability to perform the mitzvot of the Seder night properly, he should not fast. However, the Mishnah Berurah (670:2) recommends that in such a case, one should limit his eating to light foods, avoiding a regular meal. Other poskim (Responsa Olat Shmuel, 58, quoted in Kaf HaChaim 670:8) suggest that the proper approach would be to fast only until chatzot hayom (mid-day). 

Rav Yoseph Eliyahu Henkin, zt”l [Kitvei HaGaon Rav Y.E. Henkin, vol. 2:31] maintained that redeeming the fast with charity (i.e. donating to charity an amount that equals what one typically eats during the day) is the most recommended course of action.