Ambrose of Milan
Catena Aurea · Lukasevangelium 22
And he said unto them, When I sent you without purse, and scrip, and shoes, lacked ye any thing? And they said, Nothing. Then said he unto them, But now, he that hath a purse, let him take it, and likewise his scrip: and he that hath no sword, let him sell his garment, and buy one. For I say unto you, that this that is written must yet be accomplished in me, And he was reckoned among the transgressors: for the things concerning me have an end. And they said, Lord, behold, here are two swords. And he said unto them, It is enough.
Or, because the law does not forbid to return a blow, perhaps He says to Peter, as he is offering the two swords, It is enough, as though it were lawful until the Gospel; in order that there may be in the law, the knowledge of justice; in the Gospel, perfection of goodness. There is also a spiritual sword, that you may sell your patrimony, and buy the word, by which the nakedness of the soul is clothed. There is also a sword of suffering, so that you may strip your body, and with the spoils of your sacrificed flesh purchase for yourself the sacred crown of martyrdom. Again it moves, seeing that the disciples put forward two swords, whether perhaps one is not of the Old Testament, the other of the New, whereby we are armed against the wiles of the devil. Therefore the Lord says, It is enough, because he wanted nothing who is fortified by the teaching of both Testaments.