Rabanus Maurus
Catena Aurea · Matthäusevangelium 16
When Jesus came into the coasts of Cæsarea Philippi, he asked his disciples, saying, Whom do men say that I the Son of man am? And they said, Some say that thou art John the Baptist; some, Elias; and others, Jeremias, or one of the prophets. He saith unto them, But whom say ye that I am? And Simon Peter answered and said, Thou art the Christ, the Son of the living God. And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven. And I say also unto thee, That thou art Peter, and upon this rock I will build my Church: and the gates of hell shall not prevail against it. And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
But this power of binding and loosing, though it seems given by the Lord to Peter alone, is indeed given also to the other Apostles, and is even now in the^ Bishops and Presbyters in every Church. (vid. Matt. 18:18.) But Peter received in a special manner the keys of the kingdom of heaven, and a supremacy of judicial power, that all the faithful throughout the world might understand that all who in any manner separate themselves from the unity of the faith, or from communion with him, such should neither be able to be loosed from the bonds of sin, nor to enter the gate of the heavenly kingdom.