Tisha B'Av (the ninth day of the Hebrew month of Av) usually occurs in the Gregorian calendar during July or August. The Fast of the Ninth of Av is a day of mourning to commemorate the many tragedies that have befallen the Jewish people, many of which coincidentally have occurred on the ninth of Av. The worst of the tragedies occurred on the 9th of Av; most notably was the destruction of both Temples. (the first by the Babylonians in 586 B.C.E., the second by the Romans in 70 C.E.).

Although this holiday is primarily meant to commemorate the destruction of the Temple, it is appropriate to consider the many other tragedies that transpired. In chronological order, its source began with the sin of the spies who lied pessimistically about the land of Israel to the Jewish nation (noted in the Book of Bamidbar). Ever since, God had given the nation real reason to mourn in correction of this lack of faith. Throughout history, the Temples burned, the Jews were expelled from Spain in 1492, Pogroms and World War I and II have all occurred on this momentous day. In the future this day of mourning will completely turn into a day of rejoicing as the true Moshiach will be born on this day removing the yoke of the nations around us.

Tisha B'Av is the culmination of a three-week period of increased mourning, beginning with the fast of the 17th of Tammuz, which commemorates the first breach in the walls of Jerusalem, before the First Temple was destroyed. During this three-week period, weddings and other parties are not permitted, and people refrain from cutting their hair. From the first to the ninth of Av, it is customary to refrain from eating meat or drinking wine (except on the Shabbat) and from wearing new clothing.

Tisha B'Av is an appropriate time for all Jews to mourn what we have lost.  Many of the customs of mourning are in effect during this period, which gives us the opportunity to look deeply into our lives and mourn for what we once had. Mourning requires that we attentively observe our feelings of what has departed from our lives. There’s not much else to do but observe the feelings as they arise without fleeing from them. The more diligently we’re willing to face the feelings, the sooner they will depart from our lives. The feelings that accompany loss are often painful, but the effort of making full use of these weeks of grieving is highly cathartic and purifying. Tisha B'Av is an ideal opportunity for us to complete the process of healing as an entire community.

The restrictions on Tisha B'Av are similar to those on Yom Kippur: to refrain from eating and drinking (even water); washing, bathing, shaving or wearing cosmetics; wearing leather shoes; engaging in sexual relations; and studying Torah. Work in the ordinary sense of the word is also restricted. People who are ill need not fast on this day. Many of the traditional mourning practices are observed: people refrain from smiling, laughter and idle conversation, and sit on low stools.

In synagogue, the book of Lamentations is read and mourning prayers are recited. The ark (cabinet where the Torah is kept) is draped in black.

The physical connection of the entire Jewish people to Jerusalem comes to the forefront when King David conquered it from the Jebusites and paid for the holy site on the Temple Mount and made the city his capital. After the destruction of the First Temple, the majority of the Jewish population was swept into exile in Babylon, by whose rivers they swore to weep for Zion, "If I forget thee, O Jerusalem, may my right hand forget its cunning. May my tongue cleave to the roof of my mouth, if I do not remember you, if I do not place Jerusalem above all my joy." In the Maccabean era, the very essence of the battle for Jerusalem was to establish the Jewish nature of the city, drive out pagan practices from Temple ritual and Hellenism from public life. Under other circumstances, there might have been no national uprising against Jewish subordination to the Greeks.
The importance of Jerusalem as a national symbol grew with subsequent periods of foreign domination: during the Great Rebellion and the Bar Kochba Rebellion,coins were minted in memory of Jerusalem.

It is, however, only after the destruction of the Second Temple that the significance of Jerusalem is transformed into that which we know today— a focal point, around which Jewish life turns toward which the entire Jewish people's national aspirations and messianic hopes are directed. Thus, we find that not only is this a spiritual connection, but also a physical one: all synagogue interiors around the world are built facing Jerusalem. Indeed, the daily and festival prayers abound in references to Jerusalem in lengthy text; the liturgy contains five major blessings relating to Jerusalem, while many other community and home rituals also describe and commemorate the Holy City.

Jerusalem is the major topic of pre-modern Hebrew poetry, and the Kinot— the mediaeval and subsequent mourning liturgy of Tisha Be'av focus time and again on Jerusalem as they lament the trials of the Jewish people throughout its history of exile. As the inevitable cycle of life continues and repeats, traditions connected with Jerusalem have been enshrined to remind us that even joy is not complete without Jerusalem: a plate is broken at the signing of an engagement contract, a groom breaks a glass under the bridal canopy after the ceremony; one small section of the wall in every new house is left unplastered or unpainted - incomplete.

For generations, it was impossible for most Jews to dream of living in Jerusalem themselves, but they participated by supporting those communities which resided there, hosting guests who had travelled from Jerusalem to raise funds. This was more than a form of charity: it brought Jerusalem to everyone and everyone to Jerusalem - a way of life. Diaspora Jewish life would be incomplete without Jerusalem: the hope for redemption and for the return of the people to Eretz Yisrael has always focused on Jerusalem. It is a longing and a hope which are most poignantly felt and expressed on Tisha B' Av.