If you are offering your gift at the altar and there remember that your brother has something against you, leave your gift there before the altar and go. First be reconciled to your brother, and then come and offer your gift. (Matt. 5:23-24)Jewish tradition says that at Yom Kippur, God only forgives sins we've commited against Him. The sins we've committed against other people, we have to go and ask forgiveness for. Yeshua taught the same thing, and he was pretty serious about it:
Come to terms quickly with your accuser while you are going with him to court, lest your accuser hand you over to the judge, and the judge to the guard, and you be put in prison. Truly, I say to you, you will never get out until you have paid the last penny. (Matt. 5:25-26)
So what are you waiting for?