1 What Pilate said to Christ, or what He replied to Pilate, has to be considered and handled in the present discourse. For after the words had been addressed to the Jews, “Take ye him, and judge him according to your law,” and the Jews had replied, “It is not lawful for us to put any man to death, Pilate entered again into the judgment hall, and called Jesus, and said unto Him, Are you the King of the Jews? And Jesus answered, Do you say this thing of yourself, or did others tell it you of me?”
The Lord indeed knew both what He Himself asked, and what reply the other was to give; but yet He wished it to be spoken, not for the sake of information to Himself, but that what He wished us to know might be recorded in Scripture. “Pilate answered, Am I a Jew? Your own nation, and the chief priests, have delivered you unto me: what have you done? Jesus answered, My kingdom is not of this world. If my kingdom were of this world, then would my servants fight, that I should not be delivered to the Jews: but now is my kingdom not from hence.”
This is what the good Master wished us to know; but first there had to be shown us the vain notion that men had regarding His kingdom, whether Gentiles or Jews, from whom Pilate had heard it; as if He ought to have been punished with death on the ground of aspiring to an unlawful kingdom; or as those in the possession of royal power usually manifest their ill-will to such as are yet to attain it, as if, for example, precautions were to be used lest His kingdom should prove adverse either to the Romans or to the Jews.
But the Lord was able to reply to the first question of the governor, when he asked Him, “Are you the King of the Jews?” with the words, “My kingdom is not of this world,” etc.; but by questioning him in turn, whether he said this thing of himself, or heard it from others, He wished by his answer to show that He had been charged with this as a crime before him by the Jews: laying open to us the thoughts of men, which were all known to Himself, that they are but vain; and now, after Pilate's answer, giving them, both Jews and Gentiles, all the more reasonable and fitting a reply, “My kingdom is not of this world.”
But had He made an immediate answer to Pilate's question, His reply would have appeared to refer to the Gentiles only, without including the Jews, as entertaining such an opinion regarding Him. But now when Pilate replied, “Am I a Jew? Your own nation, and the chief priests, have delivered you to me;” he removed from himself the suspicion of being possibly supposed to have spoken of his own accord, in saying that Jesus was the king of the Jews, by showing that such a statement had been communicated to him by the Jews.
And then by saying, “What have you done?” he made it sufficiently clear that this was charged against Him as a crime: as if he had said, If you deny such kingly claims, what have you done to cause your being delivered unto me? As if there would be no ground for wonder that one should be delivered up to a judge for punishment, who proclaimed himself a king; but if no such assertion were made, it became needful to inquire of Him, what else, if anything, He had done, that He should thus deserve to be delivered unto the judge.
Source: Tractates on the Gospel of John (New Advent)