Mark 8:32

But how is this, that Peter, gifted with a revelation from the Father, has so soon fallen, and become unstable? Surely, however, it was not wonderful that one who had received no revelation concerning the Passion should be ignorant of this. For that He was the Christ, the Son of the living God, he had learnt by revelation; but the mystery of His cross and resurrection had not yet been revealed to him. He Himself, however, showing that He must come to His Passion, rebuked Peter; wherefore there follows, And when he had turned about and looked on his disciples, he rebuked Peter, &c.

(ubi sup. Chrys. ubi sup.) This, however, he speaks with the feelings of a man who loves and desires; as if he said, This cannot be, neither can mine ears receive that the Son of God is to be slain.

But His disciples did not understand the order of the truth, neither could they comprehend His resurrection, but thought it better that He should not suffer.

(Vict. Ant. e Cat. in Marc. v. Chrys. ubi sup.) The reason, however, why the Lord told them this, was to show, that after His cross and resurrection, Christ must be preached by His witnesses. Again, Peter alone, from the fervour of his disposition, had the boldness to dispute about these things. Wherefore it goes on, And Peter took him up, and began to rebuke hime.