True forgiveness means you don't judge and condemn another. There's not really any sin and guilt out there, because nothing has happened except in a dream, and dreams are not real. So J counsels you in his Course not to make the ideas of sin and guilt real in the people, events, and situations you see in the world:

"Call it not sin but madness, for such it was and so it still remains. Invest it not with guilt, for guilt implies it was accomplished in reality. And above all, be not afraid of it. When you seem to see some twisted form of the original error rising to frighten you, say only, 'God is not fear, but Love,' and it will disappear.
~ Your Immortal Reality
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