Proofs of Oral Torah: The Four Fast Days in Zechariah
In this article, we're highlighting a powerful Biblical example that illustrates the interconnectedness between Scripture and the Jewish Oral Torah through the words of the Prophet Zechariah.

In this series, we're highlighting Biblical examples that illustrate the interconnectedness of Scripture and the Jewish Oral Torah.
Though this example has been briefly mentioned in a previous work, we will spotlight this topic as it is a powerful one.
The Written and Oral Torah
In the Jewish tradition, the Torah is comprised of both a Written and Oral Torah component. These are inextricably interconnected, and vital to living out the Biblical commandments¹.
In some cases, the Rabbinic tradition may appear to add to the written commandments. The truth is, the Rabbis have only really added (7) commandments² to those found in the texts.
Nevertheless, skeptics often refuse to honor the Rabbinic commands, citing them as "unscriptural" or "legalistic."
However, there is a powerful example regarding the four fast days mentioned in Zechariah 8:19, which provides a bridge between the written Torah and the Oral tradition that is difficult to refute.
The Four Fast Days in Zechariah
Zechariah 8:19 states:
“Thus says the Lord of Hosts: The fast of the fourth month, the fast of the fifth, the fast of the seventh, and the fast of the tenth shall become joyful and glad occasions and happy festivals for the house of Judah. Therefore, love truth and peace.”
This verse refers to four fasts observed by religious Jews:
- The fast of the fourth month (Tammuz)
- The fast of the fifth month (Av)
- The fast of the seventh month (Tishrei)
- The fast of the tenth month (Tevet)
These fasts are significant as they are considered days of mourning in the Jewish tradition. Many of the events they commemorate happened, of course, after the Written Torah was consolidated—so, naturally, these days were not directly included in the (5) Books of Moses.
It is worth noting that there are a few more that are observed that mark significant events throughout time.
Scripture does not provide any further mention of these, nor the details of how they are to be observed. This is presumably because the primary audience already understood these connections.
The Rabbinic Tradition: Fasts of Mourning
For the sake of later generations, the Rabbinic literature filled in the details to ensure these observances are upheld in each generation.
Let's look at these fasts in more detail.
1. The Fast of Tammuz (17th of Tammuz)
This fast commemorates the breach of the walls of Jerusalem by the Babylonians. Rabbinic tradition has also marked this date for other calamities, including the cessation of daily sacrifices during the siege of the Temple and the breaking of the Tablets by Moses.
2. The Fast of Av (9th of Av)
The 9th of Av is a day one of the darkest days of mourning, marking the destruction of both the First and Second Temples. The Talmud in Ta’anit 29a, elaborates on other tragedies associated with this date.
It is also worth mentioning that the 9th of Av has continued to bring calamity throughout history, from the Spanish Inquisition and the events that led to the World Wars and the Holocaust.
3. The Fast of Gedaliah (3rd of Tishrei)
This fast commemorates the assassination of Gedaliah, the governor of Judah, as recounted in Jeremiah 41. His death marked the collapse of Jewish autonomy after the First Temple’s destruction.
4. The Fast of Tevet (10th of Tevet)
This fast recalls Nebuchadnezzar’s siege of Jerusalem. The Oral Torah expands on its significance as a day of mourning for the chain of events that led to the Temple’s destruction.
A Unified Framework
Zechariah's mention of these fasts highlights the interplay between the Written and Oral Torah.
In addition, without the oral tradition, the meaning of Zechariah’s reference to these fasts would lose its power. See, Zechariah foresaw that these days of mourning would ultimately become days of joy in the Messianic era.
This implies that they are important aspects of the hope and practice to remind us of the coming Messianic Kingdom.
Conclusion
The four fasts of Zechariah highlight the inseparable connection between the Bible and the Jewish Oral Torah. Together, they form a holistic framework that has sustained the Jewish people through exile and adversity, preserving their history, identity, and hope for the final redemption.
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Notes:
¹ Mitzvot and Misconceptions: Understanding the Biblical Commandments
² https://www.chabad.org/library/article_cdo/aid/3495212/jewish/What-Are-the-7-Rabbinic-Mitzvahs.htm