Tikkun Hazot are prayers recited at midnight in memory of the destruction of the Temple and for the restoration to the Land of Israel. This custom developed from the rabbinic description of God mourning the destruction. It is recorded that during the night He “sits and roars like a lion, exclaiming: ‘Woe to the children, on account of whose sins I destroyed My house and burnt My temple and exiled them among the nations of the world’” (Ber. 3a). The hour of midnight was chosen because David arose at this hour to study and pray, as it is said, “At midnight I will rise to give thanks unto Thee” (Ps. 119:62; Ber. 3b–4a). This practice became formalized under the influence of the Kabbalah during the period of Isaac Luria. Two separate forms of the service developed known as Tikkun Rahel and Tikkun Le’ah. Tikkun Rahel, consisting of Psalms 137 and 79 and Tehinnot on the destruction of the Temple, is recited on days when Tahanun is said. On the Sabbath, festivals, and days when Tahanun is omitted, Tikkun Le'ah, consisting of more joyful psalms, such as 111 and 126, and selections from the Mishnah (Tamid ch. 1), is recited.

על פי "מרפא לנפש", ליוורנו תרכ"א. דף כ,ב ואילך: סליחות וכו'.