Today, 3rd of Tishri, is the fast of Gedalia. A fast day instituted by the Rabbis to commemorate the assassination of Gedalia Ben Achiqam, the governor of Israel during the days of Nebuchadnetzar King of Babylonia (ca. 580 BCE). The fast is observed on the day immediately following Rosh haShana.
When Nebuchadnetzar destroyed the Temple (bet haMiqdash) in Yerushalayim (586 BC) and exiled the Jewish people to Babylonia, he allowed a few Jews (mainly poor farmers) to remain in the land of Israel and appointed Gedalia Ben Achiqam as their governor. As a result, many Jews returned to the land of Israel and worked the land under the auspices of the king of Babylonia. They had a new hope that eventually, more Jews might be able to return to their land.
Foreseeing this situation the king of the neighboring Ammon sent a loyal Jew, Yishma'el Ben Netania to assassinate Gedalia. In the seventh month (Tishri) Yishma'el came to Gedalia in the town of Mitzpa and was received cordially. Gedalia had been warned of his guests murderous intent, but he refused to believe his informants convinced that a Jew will never kill another Jew, and jeopardize their hopes of redemption. Yishma'el and ten of his men murdered Gedalia together with most of the Jews who had joined him in Mitzpa and numbers of Babylonians whom the Babylonian king had left with Gedalia. The remaining Jews feared the vengeance of the Babylonian king and fled to Egypt.
The surviving remnant of Jews was thus dispersed and the land of Israel remained virtually without Jews. In remembrance of these tribulations, our Sages instituted the 'Fast of the Seventh' on the day of Gedalia assassination in the seventh month.
The fast is observed from daybreak till the stars appear at night (today, September 19th, 2012 in our community we break the fast at 7.28 pm).
Adapted from www.ou.org
Who is exempted from fasting today?
Minors: boys under 13 and girls under 12 years old are completely exempted from fasting.
Nursing women: According to the Sephardic Minhag, after giving birth women are exempted from fasting for 24 months, even if they are not actually nursing their baby.
Pregnant women, especially after the first 3 months, are exempted from fasting.
A person who feels sick, for example, flu or fever or one who has a chronic disease, for example, diabetes, should not fast.
Elders should consult with their physicians if the fast will not affect their health. If it will, they are exempted (and in some cases, prohibited) from fasting.