A. This Friday is the fast day of 10 Tevet. Isn’t it unusual to fast on a Friday?
Q. First, some background to the day. It is one of four fasts enumerated in Zech. 8:19: “The fast of the 4th month (17 Tammuz), the fast of the 5th (9 Av), the fast of the 7th (3 Tishri) and the fast of the 10th (10 Tevet)”.
All these dates are associated with the destruction of the Temple. 10 Tevet marks the beginning of the siege of Jerusalem: “In the 10th month, on the 10th day of the month… this very same day the King of Babylon has invested Jerusalem” (Ezek. 24:1-2). Because Ezekiel says “this very same day”, the fast of 10 Tevet has to take place irrespective of it sometimes being Erev Shabbat.
Zechariah speaks (verse 19) of a time when the four historical fasts “shall be to the House of Judah joy and gladness, and festival seasons”. A Talmudic debate (R.H. 18b) examines the conditions under which the fasts can be dispensed with and become festivals. The accepted ruling is that the fasts are still obligatory (Shulchan Aruch, Orach Chayim 549:1), not only to commemorate past events but to arouse us to repentance (Mishnah B’ruch). With the coming of the Messiah, Zechariah’s prophecy will be realised and the four fasts will become days of rejoicing.
Of the four fasts, only one – Tishah B’Av – is, like Yom Kippur, from sunset one day to nightfall the next; the others begin at day break.