As the sun set this evening, we crossed into the 9th day of the 5th Biblical month (Av / Ab). As I pointed out in a recent podcast, The Cause of Calamitous Times, this day has historically been associated with tragedies for the people of God; the most well-known of which is the traditional dating for the destruction for two Jewish Temples. As a result of the recurring catastrophes, the Jewish people declared the day as a fast day. When, however, the 9th of Av falls on a Sabbath, the fast is moved to the following day, the 10th of Av. As it turns out, moving the fast to the 10th may in fact put the fast where it belongs in the first place.
In the Jewish Encyclopedia article on the Ninth of Ab, R. Johanan, amora of the 3rd century, is quoted as saying, “If I had been living at the time, I would have instituted the fast on the 10th rather than on the 9th of Ab.” R. Johanan’s choice of the 10th rather than the 9th puts him in agreement with the Biblical prophet Jeremiah, and the First Century historian Josephus.
Jeremiah
“On the tenth day of the fifth month — that was the nineteenth year of King Nebuchadrezzar, the king of Babylon — Nebuzaradan, the chief of the guards, came to represent the king of Babylon in Jerusalem. He burned the House of the LORD, the king’s palace, and all the houses of Jerusalem; he burned down the house of every notable person.” (Jeremiah 52:12–13 JPS)
Josephus
“God had doomed the Temple to the fire, according to the destiny of the ages, on that same fatal day, the tenth day of the month Lous (Ab), on which it was formerly burned by the king of Babylon.” “B.J.” vi. 4, § 5
So this year, on the 10th of Av, as we reflect on the destruction of two Jewish Temples, we are more than likely better aligned with our written sources than years where the observance falls on the 9th of Av.