Tractate Taanit reminds us that, in the world of the rabbis, fasting was a regular practice — not for the sake of a cleanse or some other health fad, but for spiritual and material benefit. Most often, to avert disaster.
Tractate Taanit deals with all kinds of fasts that Jews undertook: communal fasts and individual fasts, fixed fast days (like Tisha B’Av) and spontaneously-declared fast days, fasts that commemorated past tragedies, and fasts that were designed to avert present tragedies, such as famine, war and plague. Most of this tractate deals with drought — suggesting that lack of rain was perhaps the most regular tragedy to strike ancient Jewish communities. Conspicuous by its near absence is the most widely-observed Jewish fast, Yom Kippur. Unlike the other fasts that are the subject of this tractate, Yom Kippur is described as joyous. It is also covered at length in Tractate Yoma.
In general, fasting means abstaining from both food and drink and fasts were called on Mondays and Thursdays, the same days that Torah was read publicly, though they could not be held on certain joyous days. In some cases, additional restrictions applied, including refraining from bathing, anointing with oils and sex.
As this tractate makes clear, fasting is usually not enough to avert a disaster. Repentance and prayer are integral to moving God to forgiveness and mercy. The tractate has four chapters:
Since most of this tractate concerns fasts that are declared in the event of a drought, this chapter begins by establishing the dates on which rain is needed (and expected) to ensure an adequate harvest. These dates, as described in the Mishnah, are specific to the land of Israel — the Gemara acknowledges a different need in Mesopotamia.
All Jews add prayers for rain to their liturgy between Shemini Atzeret and Passover. But if time wears on without rain, then scholars start observing fasts in an effort to bring the rain. Should this fail, then the entire community fasts — initially observing three fasts days on consecutive Mondays and Thursdays. More and more severe fasts are added as needed.
In this chapter we learn that fast days entailed not just abstention from food but also focused self-reflection, repentance and prayer. The opening pages of this chapter describe many rituals that support fast days including additional prayers and readings and public acts of repentance. In extreme cases, other public displays of mourning are evoked, such as bringing the ark into the town square and covering it with ashes. In the Temple, they would blow the shofar between blessings. The chapter also deals with people who are exempt from fasting.
Fast days are not supposed to overlap with days of feasting and rejoicing. In ancient jewish times, there were a great many of these happy occasions, as recorded in a Tannaitic-era calendar called Megillat Taanit. Most of them had already fallen by the wayside by the period of the Gemara, with the exception of Hanukkah and Purim.
This chapter considers the question of what makes an event dangerous enough to the community to warrant declaring a public fast. That seems to be up to the community in question. If a disaster is fairly localized, only the people in imminent danger fast, though the larger Jewish community prays to support them.
This chapter contains many famous stories of communities facing drought and other disasters, most notably that of Honi the Circle-Drawer.
The final chapter of this tractate shifts focus to fasts that take place on fixed days, commemorating past tragedies that befell the community. The most well-known of these is Tisha B’Av which commemorates the destruction of both Temples (and several other disasters). This chapter ends by describing the celebratory occasion known as Tu B’Av (the fifteenth of Av) which is sometimes called the Jewish Valentine’s Day.