Augustine of Hippo
Catena Aurea · Johannesevangelium 16
These things have I spoken unto you, that ye should not be offended. They shall put you out of the synagogues: yea, the time cometh, that whosoever killeth you will think that he doeth God service. And these things will they do unto you, because they have not known the Father, nor me. But these things have I told you, that when the time shall come, ye may remember that I told you of them. And these things I said not unto you at the beginning, because I was with you.
(Tr. xciv. 1) In the other three Evangelists these predictions occur before the supper; John gives them after. Still if they relate them as given very near His Passion, that is enough to explain His saying, These things I said not unto you at the beginning. Matthew however relates these prophecies as given long before His Passion, on the occasion of His choosing the twelve. How do we reconcile this with our Lord’s words? By supposing them to apply to the promise of the Holy Spirit, and the testimony He would give amidst their suffering. This was what He had not told them at the beginning, and that because He was with them, and His presence was a sufficient consolation. But as He was about to depart, it was meet that He should tell them of His coming, by whom the love of God would be shed abroad in their hearts, to preach the word of God with boldness.