Tisha B’Av, also known as Ninth of Av, is the traditional day of mourning for the destruction of the temples in Jerusalem. This day usually occurs in July or August.
According to Jeremiah 3:12, the Babylonian destruction of the First Temple occurred on the tenth of Av. However, II Kings 25:89 dated the event on the seventh of Av. According to the Tosefta Ta’anit 4:10, the discrepancy is due to the destruction of the outer walls and the courtyard, which started on the seventh of Av, while the entire structure was destroyed on the tenth of Av. Although some rabbis disagree, the majority decided that it is more fitting to remember the “beginning of the calamity.”
According to Josephus, the Romans destroyed the Second Temple in 70 A.D., on the tenth of Av. The Karaites still observe this day as a day of mourning. The ninth of Av was the date recorded by the Talmud, and therefore, became accepted as the anniversary of both destructions.
The Talmud classified the ninth of Av as a major day of mourning because of these five disasters:
Based on these calamities, the ninth of Av became the symbol for all persecutions and misfortunes of the Jewish people, for the loss of national independence and for the sufferings in exile.
The Ninth of Av is the culmination of a three week period of increasing mourning, beginning with the fast on the 17th of Tammuz, which commemorates the first breach in the walls of Jerusalem, before the First Temple was destroyed. During the three week period, weddings and other parties are not permitted and people refrain from cutting their hair. Many of the traditional mourning practices are observed:
In modern Israel, besides special synagogue services to commemorate the ninth of Av, public places of entertainment and restaurants are closed on the eve on Tisha b’Av.
Ask your Jewish friends about this holiday. Do they mourn? What does the Temple mean to them? Perhaps you will get an opportunity to talk about the fact that the N.T. teaches that the indestructible temple of the Lord is in the Believers’ heart (John 2:19-21, I Cor. 3:16; 6:19).
Excerpt taken from Encyclopedia Judaica and Judaism 101.