- The 17th of Tammuz (the fourth month)
- The 9th of Av (the fifth month)
- Tzom Gedalia (the seventh month)
- The 10th of Tevet (the tenth month)
In answer to the question posed by the Gemara as to how the same day can be both a day of fasting and a day of joy, Rav Pappa explains that there are three possible scenarios that exist, which depend on the situation of the Jewish people in the world.
- If there is shalom – peace – then these are days of celebration and happiness;
- If there is shemad (or, according to some readings, gezerat malkhut) – oppression – then these are days of fasting;
- If there is neither shalom nor shemad, then it is up to the people to decide whether or not they will fast.
Defining the terms shalom and shemad (or gezerat malkhut) is not an easy task. According to the Rambam, even if the Beit HaMikdash is standing, the Jewish people may still find themselves oppressed by other nations and without full independence in their land. In such a case, they will have to fast. Many other rishonim define shalom based on whether the Temple is standing, although some refer to a situation of rov yisra’el yoshvim al admatam: if the majority of the Jewish people is living in Eretz Yisrael.
With regard to the ruling that people could choose whether or not to fast when the situation was neither shalom nor shemad, the Ritva explains that while the Temple stood, no one fasted. After the destruction of the Temple, if there was no shemad taking place, individuals chose whether or not they wanted to fast. At a later date these days became accepted by the community as fast days, and we no longer have freedom as individuals to choose whether or not to fast.