Kol Nidrei (Aramaic, all vows) is the prayer which begins the Jewish Day of Atonement evening service. It is customary for the prayer to be repeated three times, and it declares that all personal rashly made vows made to God that have not been fulfilled are cancelled. Even though the prayer has often been misunderstood by gentiles who have argued that it demonstrates that Jewish promises are worthless, in fact, the halakhah imposes serve limitations which vows can be cancelled. The German Reform rabbis removed the prayer from the Reform liturgy in 1844, in consequence of this misunderstanding, but it was restored in 1961. So poignant and popular is the prayer, that the entire evening of the Day of Atonement is often referred to as Kol Nidrei. The traditional melody was given a well-known setting by Max Bruch in 1880. A.G.H.
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 555