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.
For as with a zeal beyond the others he had confessed the King of heaven, he is deservedly entrusted more than the others with the keys of the heavenly kingdom, that it might be clear to all, that without that confession and faith none ought to enter the kingdom of heaven. By the keys of the kingdomHe means discernment1 and power; power, by which he binds and looses, discernment, by which he separates the worthy from the unworthy.