This is not a very big subject among Quakers. Sin is not a big subject there. Why? because too many of us got out minds choked by ‘jacklegged preachers’ threatening us with hell; so it’s become a dead issue.
But, not just a Quaker, sin is a real issue with me. Likewise forgiveness: Blake said it best “throughout Eternity I forgive you; you forgive me.” It’s the basic interpersonal dimension of Christianity. It’s the work of the Holy Spirit whenever we let it happen. When we refuse, we block God’s work.
God is love; loving, at least a big part of it, is forgiving. To forgive is that of God in us.