When did the Jewish community start fasting for tammuz

The fast of the 17th of Tammuz (Shiva Asar b'Tammuz) has its roots going back to the Biblical era, with formal rabbinic codification during or after the Second Temple period. The fast commemorates the breaching of Jerusalem's walls and other national tragedies, and is mentioned explicitly by the prophet Zechariah.

Key Takeaways

The fast of the 17th of Tammuz is rooted in the Biblical period, referenced in Zechariah 8:19 as the "fast of the fourth month."
The Mishnah in Ta'anit 4:6 lists five tragedies that occurred on this date, giving the fast its formal structure.
The fast was suspended during the First Temple era when Israel was sovereign, then reinstated after the Temple's destruction.
During the Babylonian exile, the fast was observed; during the Second Temple period it was debated; after the Second Temple's destruction it became firmly established.
The Talmud teaches that in the messianic future, this fast will be transformed into joy, as Zechariah prophesied.

The Biblical Foundation

The earliest reference to a fast in Tammuz comes from the prophet Zechariah, writing after the return from Babylonian exile:

"כֹּה אָמַר ה' צְבָאוֹת צוֹם הָרְבִיעִי... יִהְיֶה לְבֵית יְהוּדָה לְשָׂשׂוֹן וּלְשִׂמְחָה" "Thus says the Lord of Hosts: The fast of the fourth month [Tammuz]... shall become joy and gladness for the House of Judah." [Zechariah 8:19]

The "fast of the fourth month" refers to Tammuz (the fourth month of the Jewish year), confirming this fast was already practiced in the early Second Temple period, ca. 518 BCE.

The Historical Origins

The fast commemorates events tied to the destruction of Jerusalem. The Mishnah lists five calamities that occurred on the 17th of Tammuz:

"חֲמִשָּׁה דְבָרִים אֵרְעוּ אֶת אֲבוֹתֵינוּ בְּשִׁבְעָה עָשָׂר בְּתַמּוּז" "Five things happened to our ancestors on the 17th of Tammuz" [Mishnah Ta'anit 4:6]

The five events listed are:

The Tablets of the Torah were broken by Moshe upon seeing the Golden Calf
The daily Temple offering (tamid) was cancelled during the First Temple siege
The walls of Jerusalem were breached (during the Roman siege, 70 CE)
Apostemos burned a Torah scroll
An idol was placed in the Temple sanctuary

A Complex Timeline: When Was the Fast First Observed?

First Temple Period

The fast likely originated after the destruction of the First Temple (586 BCE), when the Jews in exile began marking national days of mourning. The "fast of the fourth month" in Zechariah refers to this exilic practice.

Second Temple Period

When the Jews returned from Babylon and rebuilt the Temple, there was a famous debate about whether to continue fasting. In Zechariah chapters 7-8, people ask whether they should still fast — and God's answer is ambiguous, emphasizing that the fasts will eventually become festivals. This suggests the fast was observed but debated during this era.

After the Second Temple's Destruction (70 CE)

The fast was definitively reestablished by the Rabbis after the Romans destroyed the Second Temple. The Mishnah in Ta'anit 4:6 formally codified it, now adding the breaching of Jerusalem's walls in 70 CE to its list of tragedies.

The Ritva [Ritva, Rosh Hashanah 18b] notes an important distinction: Tisha B'Av is considered more severe than the 17th of Tammuz because its tragedies were doubled — the Temple was destroyed twice on Tisha B'Av — whereas the calamities of 17 Tammuz were not equally doubled across both destructions.

A Notable Discrepancy

The Mishnah says the walls were breached on the 17th of Tammuz (during the Second Temple/Roman period). However, Jeremiah 39:2 states the walls were breached on the 9th of Tammuz during the First Temple/Babylonian period.

The Talmud resolves this: the 9th of Tammuz applies to the First Temple's destruction, while the 17th of Tammuz applies to the Second Temple. Since the Second Temple's destruction was the more recent and defining trauma, the 17th became the fixed fast date. [Rashi, Shevuot 10a, Ta'anit discussion]

The Messianic Promise

Zechariah's prophecy [8:19] promises that in the future, the fast of Tammuz — along with the fasts of the 5th, 7th, and 10th months — will be transformed into days of sason v'simcha (joy and gladness). This gives the fast an inherently hopeful, forward-looking dimension: we fast not merely in grief, but in anticipation of future redemption.

For personal guidance on fasting practices, consult your local rabbi or posek.