Tzom Gedaliah (Hebrew: צום גדליה) , meaning The Fast of Gedalia , is a Jewish fast day instituted by our Sages to commemorate the murder of Gedaliah Ben Achikam, the righteous governor of Judah during the days of Nebuchadnetzar King of Babylonia. After Gedaliah’s death , the final vestiges of Judean autonomy were destroyed, thousands of Jews were killed and the remaining Jews were driven into Exile.
The fast is mentioned in Zechariah 7:5-
“אֱמֹר אֶל-כָּל-עַם הָאָרֶץ, וְאֶל-הַכֹּהֲנִים לֵאמֹר: כִּי-צַמְתֶּם וְסָפוֹד בַּחֲמִישִׁי וּבַשְּׁבִיעִי, וְזֶה שִׁבְעִים שָׁנָה–“הֲצוֹם צַמְתֻּנִי, אָנִי
” Speak unto all the people of the land, and to the priests, saying: When ye fasted and mourned in the fifth and in the seventh month, even these seventy years, did ye at all fast unto Me, even to Me?”
The fast is observed on the third of Tishrei, the day following the 2 days of Rosh HaShanah. During the 25 hours of the fast, one should not drink or eat.
Many scholars claim Gedaliah was killed on the first day of Tishrei, but the fast was postponed till after Rosh HaShanah, since fasting is prohibited during the Holiday. Some Rabbis have said that its aim is to establish that the death of the righteous is likened to the burning of the First Temple.
Just as they ordained a fast upon the destruction of the Sanctuary, they ordain a fast upon the death of Gedaliah.