Protestant fundamentalists, even after being shown John 20:23, insist that priests have no authority to forgive sins, and that only God can forgive sins- rendering the Sacrament of Confession invalid. Could this statement be accurate and not disproving of the validity of the sacrament, if God is essentially granting forgiveness through the priest? Or rather, God using the priest to forgive the sin(s)?
Let us begin by looking at the Catechism:
1441 Only God forgives sins. Since he is the Son of God, Jesus says of himself, “The Son of man has authority on earth to forgive sins” and exercises this divine power: “Your sins are forgiven.” Further, by virtue of his divine authority he gives this power to men to exercise in his name.
1442 Christ has willed that in her prayer and life and action his whole Church should be the sign and instrument of the forgiveness and reconciliation that he acquired for us at the price of his blood. But he entrusted the exercise of the power of absolution to the apostolic ministry which he charged with the “ministry of reconciliation.” The apostle is sent out “on behalf of Christ” with “God making his appeal” through him and pleading: “Be reconciled to God.”
The priest may be likened to a judge in court. Judges acts on behalf of the law they do not act of their own accord, however, it is still the individual judge who is performing the action. In a similar way, when sins are forgiven in confession it is God who forgives through the individual actions of the priest. The priest does not do this of his own accord but on behalf of Christ who gave his apostles that authority:
[Jesus] breathed on [the apostles] and said to them, "Receive the holy Spirit. Whose sins you forgive are forgiven them…