Prayer recited in the synagogue at the beginning of the evening service on the Day of Atonement; the name is taken from the opening words. The "Kol Nidre" has had a very eventful history, both in itself and in its influence on the legal status of the Jews. Introduced into the liturgy despite the opposition of rabbinic authorities, repeatedly attacked in the course of time by many halakists, and in the nineteenth century expunged from the prayer-book by many communities of western Europe, it has often been employed by Christians to support their assertion that the oath of a Jew can not be trusted.
Before sunset on the eve of the Day of Atonement, when the congregation has gathered in the synagogue, the Ark is opened and two rabbis, or two leading men in the community, take from it two Torah-scrolls. Then they take their places, one on each side of the ḥazzan, and the three recite in concert a formula beginning with the words , which runs as follows:
"In the tribunal of heaven and the tribunal of earth, by the permission of God—blessed be He—and by the permission of this holy congregation, we hold it lawful to pray with the transgressors."
Thereupon the cantor chants the Aramaic prayer beginning with the words "Kol Nidre," with its marvelously plaintive and touching melody, and, gradually increasing in volume from pianissimo to fortissimo, repeats three times the following words:
"All vows , obligations, oaths, and anathemas, whether called 'ḳonam,' 'ḳonas,' or by any other name, which we may vow, or swear, or pledge, or whereby we may be bound, from this Day of Atonement until the next (whose happy coming we await), we do repent. May they be deemed absolved, forgiven, annulled, and void, and made of no effect; they shall not bind us nor have power over us. The vows shall not be reckoned vows; the obligations shall not be obligatory; nor the oaths be oaths."
The leader and the congregation then say together:(Num. xv. 26).
"And it shall be forgiven all the congregation of the children of Israel, and the stranger that sojourneth among them, seeing all the people were in ignorance"
This also is repeated three times. The ḥazzan then closes with the benediction, : "Blessed art thou, O Lord our God, King of the Universe, who hast preserved us and hast brought us to enjoy this season." In many congregations Num. xiv. 19-20 is recited before this benediction. After it the Torah-scrolls are replaced, and the customary evening service begins.
The tendency to make vows was so strong in ancient Israel that the Pentateuchal code found it necessary to protest against the excessive estimate of the religious value of such obligations (Deut. xxiii. 23). Rash and frequent vows inevitably involved in difficulties many who had made them, and thus evoked an earnest desire for dispensation from such responsibilities. This gave rise to the rite of absolution from a vow ("hattarat nedarim") which might be performed only by a scholar ("talmid ḥakam"), or an expert ("mumḥeh") on the one hand, or by a board of three laymen on the other. On account of the passionate nature of the Jews and of Orientals in general, however, and in view of their addiction to making vows, it might easily happen that these obligations would afterward be wholly forgotten and either not be kept or be violated unintentionally (see L. Löw, "Die Dispensation von Gelöbnissen," in "Gesammelte Schriften," iii. 361 et seq.). The religious consciousness, which felt oppressed at the thought of the non-fulfilment of its solemn vows, accordingly devised a general and comprehensive formula of dispensation which was repeated by the ḥazzan in the name of the assembled congregation at the beginning of the fast of Atonement. This declared that the petitioners, whowere seeking reconciliation with God, solemnly retracted in His presence all vows and oaths which they had taken during the period intervening between the previous Day of Atonement and the present one, and made them null and void from the beginning, entreating in their stead pardon and forgiveness from the Heavenly Father.
This is in accordance with the older text of the formula as it is preserved in the "Siddur" of Amram Gaon (ed. Warsaw, i. 47a) and in the "Liḳḳuṭe ha-Pardes" (p. 12b). The "Kol Nidre" was thus evidently developed from the longing for a clear conscience on the part of those seeking reconciliation with God. The date of the composition of the prayer and its author are alike unknown; but it was in existence at the geonic period.