4 “And when He had thus spoken, one of the officers who stood by gave Jesus a blow with his open hand, saying, Do you answer the high priest so? Jesus answered him, If I have spoken evil, bear witness of the evil; but if well, why do you smite me?” What could be truer, meeker, juster, than such an answer? For it is His [reply], from whom the prophetic voice had issued before, “Make for your goal (literally, take aim), and advance prosperously and reign, because of truth, and meekness, and righteousness.” If we con sider who it was that received the blow, might we not well feel the wish that he who struck it were either consumed by fire from heaven, or swallowed up by the gaping earth, or seized and carried off by devils, or visited with some other or still heavier punishment of this kind?
For what one of all these could not He, who made the world, have commanded by His power, had He not wished rather to teach us the patience that overcomes the world? Some one will say here, Why did He not do what He Himself commanded? for to one that smote Him, He ought not to have answered thus, but to have turned to him the other cheek. Nay, more than this, did He not answer truthfully, and meekly, and righteously, and at the same time not only prepare His other cheek to him who was yet again to smite it, but His whole body to be nailed to the tree?
And hereby He rather showed, what needed to be shown, namely, that those great precepts of His are to be fulfilled not by bodily ostentation, but by the preparation of the heart. For it is possible that even an angry man may visibly hold out his other cheek. How much better, then, is it for one who is inwardly pacified to make a truthful answer, and with tranquil mind hold himself ready for the endurance of heavier sufferings to come? Happy is he who, in all that he suffers unjustly for righteousness' sake, can say with truth, “My heart is ready, O God, my heart is ready;” for this it is that gives cause for that which follows: “I will sing and I give praise;” which Paul and Barnabas could do even in the cruellest of bonds.
Source: Tractates on the Gospel of John (New Advent)