Luke 22:49

Seeing what was to happen, those around him said: Lord, shall we strike with the sword? And one of them struck the servant of the high priest and cut off his right ear. Peter did this, as the evangelist John teaches, with the same fervor of mind with which he had done other things. For he knew how Phinehas received the reward of righteousness and everlasting priesthood by punishing the sacrilegious. What follows:

The blessed disciples, wounded with the prodding of divine love, drew their swords to repel the attack. Christ would not permit this, but he rebuked Peter, saying, "Put your sword into its sheath; for all who have taken swords shall die by swords." In this, he gave us a pattern of the way in which we must hold on by our love for him and of the extent to which the burning zeal of our piety may proceed. He does not want us to use swords to resist our enemies. He would rather have us use love and prudence.… The Savior moderates the unmeasured heat of the holy apostles. By preventing the example of such an act, he declares that those who are the leaders in his religion have no need in any way whatsoever of swords. With divine dignity, Christ healed him who received the blow and gave this godlike sign for their condemnation to those who came to seize him.

(de Con. Ev. lib. iii. c. 5.) Now Luke says, But Jesus answered and said, Suffer ye thus far; which is what Matthew records, Put thy sword up into its sheath. Nor will it move you as contrary thereto, that Luke says here that our Lord answered, Suffer ye thus far, as if He had so spoken after the blow to show that what was done had pleased Him so far, but He did not wish it to proceed farther, seeing that in these words which Matthew has given, it may rather be implied that the whole circumstance in which Peter used the sword was displeasing to our Lord. For the truth is, that upon their asking, Lord, shall we strike with the sword? He then answered, Suffer ye thus far, that is, be not troubled with what is about to happen. They must be permitted to advance so far, that is, to take Me, and so to fulfil the things which were written of Me. For he would not say, And Jesus answering, unless He answered this question, not Peter's deed. But between the delay of their words of question to our Lord and His answer, Peter in the eagerness of defence struck the blow. And two things cannot be said, though one may be said and another may be done, at the same time. Then, as Luke says, He healed him who was struck, as it follows, And he touched his ear, and healed him.