Contributed by: Eliyahou Kitov
On the day immediately following Rosh Hashanah "the third of Tishrei" we observe the Fast of Gedalyah. In Scripture (Zecharyah 7:5), this fast is referred to as the "the fast of the seventh," since it is observed in Tishrei, the seventh month counting from Nisan. If Rosh Hashanah falls on a Thursday and Friday, the fast is postponed until Sunday, the fourth of Tishrei, since public fasts (with the sole exception of Yom Kippur) are not held on Shabbat.
The fast is observed from daybreak until the appearance of the stars at night. In the repetition of the Amidah in Shacharit, the prayer leader recites Anenu. The Torah is removed from the aron kodesh, and the passages of Veyechal (Shemos 32:11 -14 and 34:1 -10) are read. This fast was ordained by the Sages to commemorate the assassination of Gedalyah ben Achikam, who was killed by Yishma'el ben Nesanyah at the instigation of the King of Ammon. With Gedalyah's death, the last ember of Jewish autonomy in the aftermath of the destruction of the first Beis ha-Mikdash was extinguished. Thousands Jews were killed, and those who remained alive were driven into exile.
When Nebuchadnezzar, King of Babylonia, destroyed the Beis ha-Mikdash and drove the people into exile, he allowed a remnant to remain in the Land of Israel, appointing Gedalyah as his governor. | Those Jews who had fled to Moab, Ammon, Edom, and other neighboring countries returned to the land and cultivated the areas that the Babylonian king had granted them. They tended the vineyards and enjoyed a new respite from their earlier oppression.
Their respite was to be brief, however. The King of Ammon was hostile and envious and dispatched Yishma'el to assassinate Gedalyah.
In Tishrei, Yishma'el approached Gedalyah in the town of Mitzpeh. Though Gedalyah had been forewarned as to Yishma'el's intentions, he did not believe the reports that he had received, for he considered them to be slander. He received Yishma'el and accorded him great honor. Yishma'el murdered Gedalyah and many of the Jews who were in attendance, as well as the Casdian guard that Nebuchadnezzar had provided for his governor. Those Jews who remained in the Land of Israel feared the inevitable retribution of the Babylonian king and fled to Egypt. Thus, the remnant that had been left in the land was dispersed and the land was left desolate.
In commemoration of these tragic events, the Sages established the "fast of the seventh month" on the day that Gedalyah was assassinated. Regarding this fast our Sages (Rosh Hashanah 18b) said: "This teaches us that the death of the righteous is equivalent to the burning of the House of God, for just as a fast was ordained to commemorate the destruction of the Beis ha-Mikdash, so too was a fast ordained to commemorate the death of Gedalyah."