Sermon by St. Augustine the Bishop
The Lord Jesus told his disciples what things they should suffer after that he was gone away from them, and then (as John recordeth) he said: These things I said not unto you at the beginning, because I was with you; but now I go my way to him that sent me. The first thing to be noticed here is, whether he had not already told them of their future sufferings. That he had done so amply before the night of the Last Supper, is testified by the other three Evangelists; but according to John, it was when that Supper was ended, that he said: These things I said not unto you at the beginning, because I was with you.
Are we then to try to loose the knot of this difficulty by asserting that, according to these three Evangelists, it was on the eve of the passion, albeit before the Supper, that he had said these things unto them, and therefore not at the beginning, when he was with them, but when he was about to leave them, and go his way to the Father? And in this way we might reconcile the truthfulness of what this Evangelist saith here: These things I said not unto you at the beginning: with the truthfulness of the other three. But this explanation is rendered impossible by the Gospel according to Matthew, who telleth us how that the Lord spake to his Apostles concerning their sufferings to come, not only when he was on the point of eating the passover with them, but at the very beginning, when the names of the twelve were first given, and they were sent forth to do the work of God.
It would seem then that when he said: These things I said not unto you at the beginning, because I was with you: he meant by These Things, not the sufferings, which they were to bear for his sake, but his promise of the Comforter who should come to them, and testify while they suffered. This Comforter then, or Advocate (for the Greek word Paraclete may be interpreted in both senses), would be needful to them when they saw Christ no more; and therefore it was that Christ spoke not of the Holy Spirit at the beginning while he himself was with his disciples, because his visible presence was then their sufficient Comfort.