Jesus Christ had power to forgive sins, and he conferred this power on the apostles and, through their successors the bishops, on priests. Although priests are sinners themselves, they have Christ’s authority to forgive sins through the sacrament of confession.
“And there people brought to him a paralytic lying on a stretcher. When Jesus saw their faith, he said to the paralytic, ‘Courage, child, your sins are forgiven.’ At that, some of the scribes said to themselves, ‘This man is blaspheming.’ Jesus knew what they were thinking, and said, ‘Why do you harbor evil thoughts? Which is easier, to say, “Your sins are forgiven,” or to say, “Rise up and walk”? But that you may know that the Son of Man has authority on earth to forgive sins,’ he then said to the paralytic, ‘Rise, pick up your stretcher, and go home.’ He rose and went home. When the crowds saw this they were struck with awe and glorified God who had given such authority to human beings” (Matt. 9:2-8).
“Whoever listens to you listens to me. Whoever rejects you rejects me. And whoever rejects me rejects the one who sent me” (Luke 10:16).
“[Jesus] said to them again, ‘Peace be with you. As the Father has sent me, so I send you.’ And then he breathed on them and said to them, ‘Whose sins you forgive are forgiven them, and whose sins you retain are retained'” (John 20:21-23).
“And all this is from God, who has reconciled us to himself through Christ and given us the ministry of reconciliation, namely, God was reconciling the world to himself in Christ, not counting their trespasses against them and entrusting to us the message of reconciliation. So we are ambassadors for Christ, as if God were appealing through us” (2 Cor. 5:18-20).