Why do Jews fast on Tisha B’Av?

Five tragedies

The Mishnah lists five events that occurred on the 9th of Av: the decree in the desert that the generation of the spies would not enter the land; the destruction of the First Temple and the Second; the fall of Betar in the Bar Kochba revolt; and the ploughing of Jerusalem. Later generations associated other disasters with the period, such as the expulsion from Spain in 1492.

How it is kept

The fast lasts from sunset to nightfall. Like Yom Kippur it forbids eating, drinking, washing, anointing, leather shoes and marital relations; in addition Torah study is limited to sad topics. In the evening the Book of Lamentations (Eichah) is chanted in a dim synagogue, and in the morning kinot (dirges) are recited while sitting on the floor. Tallit and tefillin are worn only at the afternoon prayer.

Mourning and hope

The three weeks before it are a time of increasing mourning. The sages taught that the Second Temple was destroyed because of baseless hatred, so the day is also a call to kindness. A tradition says the Messiah will be born on Tisha B’Av – a day of mourning that will become a festival (Zechariah 8:19).

Who is exempt

Pregnant and nursing women fast on Tisha B’Av, but anyone who is ill, and a woman within thirty days after childbirth, does not need to; when Tisha B’Av falls on Shabbat it is postponed to Sunday and the rules are more lenient. Ask a rabbi in case of doubt.