Pseudo-Chrysostom — as excerpted in the Catena Aurea on Mark 9:9-13

“(Vict. Ant. e Cat. in Marc.) Or else, the disciples asked Jesus, how it was written that the Son of man must suffer? Now in answer to this, He says, As John came in the likeness of Elias, and they evil intreated him, so according to the Scriptures must the Son of man suffer.”