“Let no man say within himself: ‘I repent in secret to the Lord.  God, who has power to pardon me, knows the inmost sentiments of my heart.’  Was there, then, no reason for saying ‘whatsoever you loose on earth, shall be loosed in heaven.’ [Mt. 18:18] no reason why the keys were given to the Church of God?” (Lib. 1 Hom. 49.)

St. Augustine, on confession to priests