Passover Eve

Fast of the firstborn
J. M. W. Turner's depiction of the Plague of the Firstborn (The Tenth Plague of Egypt, 1802)
Official name	Hebrew: תענית בכורות‎ (Ta'anit B'chorot) or תענית בכורים‎ (Ta'anit B'chorim). Translation: "Fast of the firstborn"
Observed by	Judaism and Jews
Type	Judaism
Significance	This fast commemorates the salvation of the Israelite firstborns during the Plague of the Firstborn
Observances	fasting
Begins	14th day of Nisan at dawn (12th day of Nisan whenever Passover begins on Sunday)
Ends	14th day of Nisan (or the 12th day as above)
2016 date	April 22
2017 date	April 10
2018 date	March 30
2019 date	April 18
Related to	Passover

Hebrew: תענית בכורות‎ (Ta'anit B'chorot) or תענית בכורים‎ (Ta'anit B'chorim).

Fast of the Firstborn (Hebrew: תענית בכורות‎‎, Ta'anit B'khorot or תענית בכורים‎, Ta'anit B'khorim); is a unique fast day in Judaism which usually falls on the day before Passover (i.e. the fourteenth day of Nisan, a month in the Jewish calendar. Passover always begins on the fifteenth of the Hebrew month). Usually, the fast is broken at a siyum celebration (typically made at the conclusion of the morning services), which, according to prevailing custom, creates an atmosphere of rejoicing that overrides the requirement to continue the fast (see Breaking the fast below). Unlike all other Jewish fast days, only firstborns are required to fast on the Fast of the Firstborn.

This fast commemorates the salvation of the Israelite firstborns during the Plague of the Firstborn (according to the Book of Exodus, the tenth of the ten plagues wrought upon Ancient Egypt prior to the Exodus of the Children of Israel), when, according to Exodus (12:29): "...God struck every firstborn in the Land of Mitzrayim (Ancient Egypt)...."

The origins of the Fast of the Firstborn are found in the Talmud, and the custom may have existed even prior to Talmudic times. The primary Talmudic source quoted for this custom is found in Tractate Soferim (21:3), where it is stated that firstborns fast "in commemoration of the miracle that they were saved from the Plague of the Firstborn."Rabbeinu Asher, in his comprehensive halakhic commentary on the Babylonian Talmud (Pesachim 10:19), as well as Rabbeinu Aharon HaKohein in his Orchot Chayyim (p. 76, §13), quote the Jerusalem Talmud (Pesachim 68a) as an additional source for the fast.