Origen
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.
It must be enquired in this place whether, when they were first sent out, the disciples knew that He was the Christ. For this speech shews that Peter then first confessed Him to be the Son of the living God. And look whether you can solve a question of this sort, by saying that to believe Jesus to be the Christ is less than to know Him; and so suppose that when they were sent to preach they believed that Jesus was the Christ, and afterwards as they made progress they knew Him to be so. Or must we answer thus; That then the Apostles had the beginnings of a knowledge of Christ, and knew some little concerning Him; and that they made progress afterwards in the knowledge of Him, so that they were able to receive the knowledge of Christ revealed by the Father, as Peter, who is here blessed, not only for that he says, Thou art the Christ, but much more for that he adds, the Son of the living God.