And yet Our Lord said clearly:
Jesus said to them again, Peace be with you. As the Father has sent me, even so I send you. And when he had said this, he breathed on them, and said to them, Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained.
So Our Lord gave MEN - the Apostles - this authority. What does this mean to you?
So Peter acting in the place of God can forgive anyone their sins, and their sins will be forgiven...But after Peter judges someone and doesn't want to forgive their sins, why does Peter have to retain their sins for them???