Many explanations have been made in an attempt to account for this. Each explanation is denied and disproved by those who favor some other explanation. The commonest of all is this, and it rings in the over-worked note of “persecution”: The Jews were so hounded and harried by the bloodthirsty Christians, and so brutally and viciously treated in the name of the loving Jesus (the terms are borrowed from Jewish writers) that they were compelled by wounds and starvation and the fear of death to renounce their religion and to vow that thereafter they would take the once despised Jesus for their Messiah. Therefore, say the Jewish apologists, knowing that during the ensuing year the terrible, bloodthirsty Christians would force the poor Jews to take Christian vows, the Jews in advance announced to God that all the promises they would make on that score would be lies. They would say what the Christians forced them to say, but they would not mean or intend one word of it.
That is the best explanation of all. Its weakness is that it assumes the “Kol Nidre” to have been coincident with times of “persecution,” especially in Spain. Unfortunately for this explanation, the “Kol Nidre” is found centuries before that, when the Jews were under no pressure.
In a refreshingly frank article in the Cleveland Jewish World for October 11, the insufficiency of the above explanation is so clearly set forth that a quotation is made:
“Many learned men want to have it understood that the Kol Nidre dates from the Spanish Inquisition, it having become necessary on account of all sorts of persecution and inflictions to adopt the Christian religion for appearances’ sake. Then the Jews in Spain, gathering in cellars to celebrate the Day of Atonement and pardon, composed a prayer that declared of no value all vows and oaths that they would be forced to make during the year....