Kol Nidrei is a problematic prayer. After all, at the portal to the holiest day of the year, could we not choose something more elevating than a legal text of annulment of vows? Could we not begin Yom Kippur with “Unetane Tokef” or with “Hashem Hashem El Rachum V’chanun”? What is Kol Nidrei?
Here is Rav Soloveichik’s approach (Al Hateshuva pg. 143-5):
On the eve of Yom Kippur , at sunset, as individuals and as a community come to the synagogue to stand before God and renew, by means of absolute repentance, the covenant of “You who are standing this day before the Lord your God” – that covenant which was defiled and violated through our sins. The shliach tzibbur stands at the Bima, with two distinguished members of the community, constituting a Beit Din, and they make two proclamations before the congregation:
The first proclamation declares that everyone present, without exception, is qualified to stand before God, and petition Him for acquittal … “We hereby declare it permissible to pray with the sinners.” Everyone is capable of repenting and entering the renewed covenant.
The second proclamation which the Shaliach Tzibbur says … is to declare null and void all oaths vows, binding statements and obligations which are liable to prevent the assembled congregation from entering into the covenant. As long as man is enslaved by his impulses, passions and desires; so long as man is not free of his drive for wealth and honor, luxuries and comforts, lust for power and desire for revenge – he cannot enter into the great oath which we all strive for on Yom Kippur, the day of atonement.
Man by his nature is drawn to idolatry. He allows himself to become enslaved to impulses and drives which control him, and in the end bring about his own ruin. In the end these things demand a price so high that he cannot pay, they stifle the spark of life within man and darken the light of his soul. These masters appear in various shapes and forms – in the image of false culture, in the image of the absolute state, public opinion, the culture of beauty, the passion for pleasure, the push towards permissiveness. These forms of idolatry impose oaths and vows upon man and keep him in their snare.
Yet as the Day of Atonement begins, we must liberate ourselves from their hold, and that is why we recite the “Kol Nidrei” prayer, to declare all these commitments, oaths and vows as “null and void, ineffective and non-existing.”
We enter into the sanctity of Yom Kippur by declaring our total freedom.