John Chrysostom — as excerpted in the Catena Aurea on John 18:33-38

“(Hom. lxxxiii) Or He means that He does not derive His kingdom from the same source that earthly kings do; but that He hath His sovereignty from above; inasmuch as He is not mere man, but far greater and more glorious than man: If My kingdom were of this world, then would My servants fight, that I should not be delivered to the Jews. Here He shews the weakness of an earthly kingdom, that it has its strength from its servants, whereas that higher kingdom is sufficient to itself, and wanting in nothing. And if His kingdom was thus the greater of the two, it follows that He was taken of His own will, and delivered up Himself.”