The halakhot of mourning begin on the day before Tisha BeAv, the eighth of Av, and they are expressed mainly in the laws of the last meal before the fast [seuda hamafseket].

The last meal before the fast begins, called the seuda hamafseket, is subject to certain customs of mourning. It is customary to eat this meal while sitting on the ground or on a low stool, and to partake only of bread and a single cooked food. Even this single food should be something very simple, and some even maintain that this single course should consist of those items considered to be “mourners’ food,” such as a dish of lentils. Some Ashkenazim eat an egg dipped in ashes. According to one custom, the bread eaten at this meal is also dipped in ashes. It is preferable to eat the seuda hamafseket alone, not as a group. Even if several diners eat together, at its conclusion they do not perform the zimmun. These halakhot do not apply when the eighth or ninth of Av is Shabbat.

Further reading: For more on the halakhot of mourning, see p. 82. For more on zimmun, (the reciting of: “Gentlemen, let us bless…”) before Grace after Meals, see p. 528.

In the time that is left between the end of the seuda hamafseket and the beginning of the fast, one may drink and even eat a little, but one should not eat a new meal.

Although Tisha BeAv is the most severe day of mourning, one does not recite Tahanun in the afternoon service before Tisha BeAv nor in all the prayers of Tisha BeAv itself. The source for the reason is a verse in the Book of Lamentations: “The Lord…proclaimed a festival against me to break my young men” (Lamentations 1:15). The Sages understood from here that Tisha BeAv is called a “festival,” and just as Tahanun is not said on all happy festival days, so too, on this painful “festival” no Tahanun is recited.

As the sun sets on the eighth of Av, all the laws of mourning take effect. In the synagogue, the curtain is removed from the ark. For the evening service, the brighter lights are turned off, and only a dim light is left, just enough to allow one to read from the prayer book. The congregation sits on the floor or on low stools.

Before the evening prayer is recited, it is the custom in some Sephardic communities to read the song of Ha’azinu (Deuteronomy 32:1–43) and the psalm “By the rivers of Babylon” (Psalms 137).

Some Sephardim have the custom to insert in the Amida prayer of all three daily services the Nahem paragraph (“May God comfort the mourners of Zion”), in the blessing of rebuilding Jerusalem. They also recite the paragraph of Aneinu (“Answer us, God, answer us, on the day of our fast”) in the blessing of Shome’a Tefilla, as appears in the prayer books. Others recite Aneinu in all the prayers, but add the paragraph of Nahem only in the afternoon service and, according to some customs, also in the prayer leader’s repetition of the Amida prayer of the morning service. By contrast, according to the custom of the Ashkenazim, both Aneinu and Nahem are recited by the congregation in the afternoon service only, while in the morning and afternoon prayer service the prayer leader inserts the Aneinu prayer in the Amida, after the seventh blessing.

After the Amida prayer of the evening service, the congregation sits on the ground or on low stools and the book of Lamentations is read. This is followed by the recitation of a few kinnot (lamentational poems), which appear in special Tisha BeAv books of kinnot. Next the congregation recites the Ve’ata Kadosh (“You are holy”) prayer, with minor alterations, which can be found in prayer books.

In some communities it is customary to proclaim after the recitation of kinnot: “Our brethren, children of Israel, know that today is the year such-and-such (specifying the number of years) since the destruction of our holy and glorious Temple!”