Rejoicing on Yom Kippur

Like many other tractates of the Mishnah, m. Ta‘anit concludes with words of consolation and hope, citing scriptural promises of redemption and restoration. (Manuscript evidence shows that some of these biblical citations are later additions.) The immediately preceding paragraph in m. Ta‘anit deals with the fast of the Ninth of Av, which commemorates the destruction of both the First and the Second Temples. The consolatory conclusion, which suggests the turning of fast days into days of joy, refers to a curious custom of young women going out into the fields and dancing before the young men on the fifteenth of Av and the Day of Atonement, without any further explanation. It is possible that on the Day of Atonement this followed the successful conclusion of the Temple rites and celebrated achieving atonement for another year.