Priests and the Authority to Forgive Sins

 In John 20:19-23 the apostles have locked themselves in a room, and the resurrected Jesus comes and stands in their midst. After showing them the wounds in His hands and side, He says to them, "Peace be with you. As the Father has sent me, so I send you." He then breathes on them and says, "Receive the Holy Spirit. Whose sins you forgive are forgiven them, and whose sins you retain are retained."

In the original Greek, the word "send" here means to send forth with the full authority of the sender. So when Jesus says to the apostles that He is sending them, what that means is that He is sending them out with His full authority. Does His authority include the authority to forgive sins? Of course it does, as story of Jesus healing the paralyzed man in Matthew 9:1-8 and Mark 2:1-12 shows. So the apostles received from Jesus His authority to forgive and retain sins. This authority has been passed down to every Catholic priest today through apostolic succession, and is exercised in the Church in the sacrament of Confession.