Last night's temple service is called Kol Nidre after the first two words of the opening prayer. Although Yom Kippur is called the Day of Atonement and the Day of Remembrance, Kol Nidre is actually about looking forward. In it, we specifically say from THIS Yom Kippur to the NEXT. (Disclosure, the prayer book I used last night changed it to say from LAST Yom Kippur to THIS.) This is a very important change.
What we are asking for is forgiveness in advance. All the vows and promises that we make during the coming year, we are really going to try to fulfill. However, we know that we may not keep them all. Therefore we are asking, in advance, that those we fail to fulfill be declared null and void.
For years, I was confused by this. If Yom Kippur is all about atoning for the past, why do we begin with a prayer dealing with next year? I recently came up with an answer. Now, I am not a scholar, and it is only my answer, but I offer it here to anyone for whom it might work.
We ask for forgiveness in advance in part to acknowledge that we are imperfect and likely to fail at somethings. This acknowledgement accompanied by a request to hold us blameless frees us now to atone for last years failings. We fast. We pray for forgiveness. "Eternal, remember last year when I asked you to hold me blameless for those vows I failed to keep? Well, I don't hold myself blameless and I am now asking You to forgive me."