Tisha B'Av, the ninth of Av, is the major fast of mourning in Judaism, a full day of about twenty-five hours without food or drink that stands as the low point of the year opposite Yom Kippur's solemnity. Its observance borrows the customs of a mourner sitting shiva: the Book of Lamentations is chanted in a low, grieving tone in a dimmed synagogue, worshippers sit on the floor or on low stools, the study of Torah is suspended except for texts of grief, greetings are not exchanged, and leather shoes, washing for pleasure and marital relations are set aside. It is the last and strictest of a sequence of mourning observances that intensify over the preceding three weeks and, in the final nine days, restrict meat, wine and celebration.
Its ostensible subject is the destruction of both Temples, the first by Babylon and the second by Rome, which tradition dates to the same day; but the ninth of Av has drawn to itself a long catalogue of later Jewish catastrophes, from the biblical report of the spies and the fall of Betar in the Bar Kokhba revolt to the expulsion from Spain in 1492, so that the day has become a general commemoration of national calamity. The Shabbat that follows is the first of seven of consolation, and the fast turns, in the tradition, toward the hope of restoration.