Much of Jewish life and observance is characterized by joy. There are many holidays and celebrations for happy occasions. Part and parcel of most mitzvos is to perform them with joy and an attitude of appreciation toward the Creator. However, there are times designated for mourning over our individual and collective past and for reflecting on deeds and resolving to improve our character traits. Throughout the Jewish year, there fast days to commemorate certain tragedies in Jewish history and to give us an opportunity to return to the right path.
The most well-known fast day on the Jewish calendar is Yom Kippur. It falls on the 10th of Tishrei, after the holiday of Rosh Hashana, and the Torah tells us that on this day we should “afflict ourselves” with fasting and to pray. On Yom Kippur, we are given a last chance to repent for our misdeeds in the past year, before G-d makes the final judgement (according to some opinions, the “deadline” is not until Chanukah, or even after, since nothing stands in the way of repentance.) A less “famous” fast day is on the 3rd of Tishrei, immediately after Rosh Hashana. The purpose of this fast it to repent for the execution of Gedalia, a Jewish leader. He was accused as a traitor, but the Babylonians became even more powerful after his execution.
The next fast day is on the 10th of Tevet, usually in January. This fast is from morning to evening and commemorates the beginning of the siege on Jerusalem in 422 BCE. The day before Purim is the fast of Esther. When the decree was issued against the Jewish People, Esther repented on behalf of the Jews and fasted for three days prior to appearing before the king to ask him for clemency.
On the 17th of Tammuz, which is tommorrow, there is a fast to mourn several tragedies that occured on this day, including the breaking of Jerusalem’s wall by the Romans in 70 CE. This day marks the beginning of an extended period of mourning called “The Three Weeks” culminating in Tish a B’Av, the longest fast day of the year, in which we mourn the destruction of the First and the second Temples.
Most adults are required to fast on these days, except for the elderly, pregnant women, and women who have just given birth. These people should ask a Rabbi about what to do in their situations. The most strict fast is Yom Kippur followed by Tisha B’Av. However, according the great Rabbi, Chaye Adam, that if one endangers his health by fasting, even on Yom Kippur, it is worse than a healthy person not fasting. Judaism lays aside rules on fasting for those who are ill or weak, but in any case, a Rabbi should be consulted.