John the Apostle
John 13:19BSB·traditional attribution

I am telling you now before it happens, so that when it comes to pass, you will believe that I am He.

John Calvin Reformed @genevareformer

19. I tell you this now, before it happen. By this statement he reminds his disciples that, when one of their number becomes a reprobate, this is so far from being a good reason for their being discouraged, that it ought to be a more full confirmation of their faith.

Matthew Henry Presbyterian @wholebiblehenry

We have here the discovery of Judas's plot to betray his Master. Christ knew it from the beginning; but now first he discovered it to his disciples, who did not expect Christ should be betrayed, though he had often told them so, much less did they suspect that one of them should do it. Now here, I.

Commenting on John 13:18-30

John Gill Reformed Baptist @doctorgill

Now I tell you before it come,.... That is, gave them notice of this before hand, that one of them should betray him: that when it is come to pass; and they had seen it fulfilled exactly to a tittle, and according to this Scripture: ye may believe that I am he: the Lord God omniscient, who knows and declares things before they come to...