John Chrysostom — as excerpted in the Catena Aurea on Mark 8:27-33

“(Vict. Ant. e Cat. in Marc. v. Chrys. ubi sup.) The reason, however, why the Lord told them this, was to shew, 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.”