John Chrysostom

But this seems hardly reasonable. For John was not in ignorance of His death, but was the first to preach it, saying, Behold the Lamb of God, that taketh away the sins of the world. For thus calling Him the Lamb, he plainly shews forth the Cross; and no otherwise than by the Cross did He take away the sins of the world. Also how is he a greater prophet than these, if he knew not those things which all the prophets knew, for Isaiah says, He was led as a sheep to the slaughter. (Is. 53:7.)