The "Three Weeks" between the fast days of the 17th of Tammuz and Tisha B'Av (July 9-30, 2021) have historically been days characterized by mourning and sorrow, commemorating the destruction of the Jewish Temples in Jerusalem.

According to the Rabbis, on the 17th of Tammuz Moses broke the tablets of the Holy Law after the sin of the golden calf, the continual sacrifice ceased, and the Romans breached the walls of Jerusalem in AD 70, among other tragedies. On the 9th of Av, those of the Exodus who were redeemed by Moses cried as a result of the negative report of the spies, and both Temples were destroyed, in addition to other calamities.

While there is no command to observe Tisha B’Av in the Scriptures, there are three references to the fast in the work of the prophet Zechariah (7:3,5; 8:9). The first two passages deal with the relevance of the fast in Zechariah’s day. But in the last passage Zechariah prophesies that during the Messianic Age Tisha B’Av will be turned into a feast day.