Thursday, July 27 is the ninth day of the month of Av, Tisha b’Av, on the Jewish calendar.

Tisha b’Av commemorates the destruction of the First Temple of Solomon ca. 587 BCE and the Second Temple in 70 CE in Jerusalem and is traditionally a day of fasting and mourning. Observance includes five prohibitions, the main one being a 25-hour fast. The Book of Lamentations is read in the synagogue followed by the recitation of kinos, liturgical dirges for the Temple and Jerusalem. Since the day has become associated with other major Jewish tragedies, some kinos recall other events, including the murder of the Ten Martyrs in ancient Rome, pogroms against medieval Jewish communities and the Holocaust.

According to tradition, the sin of the Ten Spies is the real origin of Tisha b’Av. In the Book of Numbers, 13:1-33 when the Israelites accepted their false report of the Promised Land, they wept, thinking God could not help them. The night the people wept and wailed was the ninth day of Av, which then became a day of weeping and misfortune for all time, according to tradition, following which the Jews were made to wander the desert for 40 years.