5 “Then says Pilate unto Him, Do you not speak unto me? Do you not know that I have power to crucify you, and have power to release you? Jesus answered: You would have no power against me, except it were given you from above: therefore he that delivered me unto you has the greater sin.” Here, you see, He replied; and yet wherever He replied not, it is not as one who is criminal or cunning, but as a lamb; that is, in simplicity and innocence He opened not His mouth. Accordingly, where He made no answer, He was silent as a sheep; where He answered, He taught as the Shepherd.
Let us therefore set ourselves to learn what He said, what He taught also by the apostle, that “there is no power but of God;” and that he is a greater sinner who maliciously delivers up to the power the innocent to be slain, than the power itself, if it slay him through fear of another power that is greater still. Of such a sort, indeed, was the power which God had given to Pilate, that he should also be under the power of Cæsar. Wherefore “you would have,” He says, “no power against me,” that is, even the little measure you really have, “except” this very measure, whatever its amount, “were given you from above.”
But knowing as I do its amount, for it is not so great as to render you altogether independent, “therefore he that delivered me unto you has the greater sin.” He, indeed, delivered me to your power at the bidding of envy, while you are to exercise your power upon me through the impulse of fear. And yet not even through the impulse of fear ought one man to slay another, especially the innocent; nevertheless to do so by an officious zeal is a much greater evil than under the constraint of fear.
And therefore the truth-speaking Teacher says not, “He that delivered me to you,” he only has sin, as if the other had none; but He says, “has the greater sin,” letting him understand that he himself was not exempt from blame. For that of the latter is not reduced to nothing because the other is greater.
Source: Tractates on the Gospel of John (New Advent)