Since circumcision and uncircumcision belonged to the one God, both therefore were annulled in Christ because of the priority given to faith, this being the faith of which it was written “the Gentiles shall believe in his name.”
If, now, he were for excluding circumcision, as the messenger of a new god, why does he say that "in Christ neither circumcision availeth anything, nor uncircumcision? For it was his duty to prefer the rival principle of that which he was abolishing, if he had a mission from the god who was the enemy of circumcision.
Furthermore, since both circumcision and uncircumcision were attributed to the same Deity, both lost their power in Christ, by reason of the excellency of faith-of that faith concerning which it had been written, "And in His name shall the Gentiles trust? " -of that faith "which," he says "worketh by love." By this saying he also shows that the Creator is the source of that grace.
Everywhere he says that faith in the gospel of Christ accords no value to rank or sex or works done with regard to the body or from the body or for the sake of the body, such as circumcision, works and other things of this kind. None of these, he says, has saving value in Christ. Circumcision is therefore vain, nor by uncircumcision do we gain value in Christ. Because we have conceived faith in him and because we have believed his promises and because through his resurrection we too rise and have suffered all things with him and rise to life with him but also through him, our faith is sure. Through this faith comes works fitting to salvation. This comes about through the love that we have for Christ and God and thus toward every human being. For it is these two relationships above all that set life straight and fulfill the whole sense of the law. They contain all the commands in the Decalogue—if it follows necessarily that he who keeps faith will also keep love, since these two fulfill all the precepts of the law of Christ.
Ver. 6. "For in Jesus Christ neither circumcision avails anything, nor uncircumcision; but faith working through love."
Observe the great boldness with which he now encounters them; Let him that has put on Christ, he says, no longer be careful about such matters. Having before said that Circumcision was hurtful, how is it that he now considers it indifferent? It is indifferent as to those who had it previously to the Faith, but not as to those who are circumcised after the Faith was given. Observe too the view in which he places it, by setting it by the side of Uncircumcision; it is Faith that makes the difference. As in the selection of wrestlers, whether they be hook-nosed or flat-nosed, black or white, is of no importance in their trial, it is only necessary to seek that they be strong and skilful; so all these bodily accidents do not injure one who is to be enrolled under the New Covenant, nor does their presence assist him.
What is the meaning of "working through love?" Here he gives them a hard blow, by showing that this error had crept in because the love of Christ had not been rooted within them. For to believe is not all that is required, but also to abide in love. It is as if he had said, Had you loved Christ as you ought, you would not have deserted to bondage, nor abandoned Him who redeemed you, nor treated with contumely Him who gave you freedom. Here he also hints at those who have plotted against them, implying that they would not have dared to do so, had they felt affection towards them. He wishes too by these words to correct their course of life.
[Circumcision] is indifferent for those who have it already before believing but not for those who are circumcised after believing. Note how he has rejected it, putting it after uncircumcision. What makes the difference is faith. For just as when one is choosing athletes, it matters nothing in this trial whether they be hook-nosed or snub-nosed, dark or fair, but all that need be looked for is that they be strong and skillful. So when a person is to be enrolled in the new covenant, the lack of these bodily trappings does no harm, just as they do no good if they be present.
He strikes them here with a great blow by showing that it is their failure to be rooted in love for Christ that has given entrance to this error. For what is looked for is not only faith but also faith abiding in love. It is as though he said, “Had you loved Christ as you ought, you would not have gone voluntarily into slavery, you would not have insulted your deliverer.” And here he also alludes obliquely to those who have plotted against them, showing that if they had love for them they would not have dared to do this. He also wishes to amend their lives through this saying.
[Lest Gentiles should say] that uncircumcision, in which “Abraham pleased God and had his faith counted for righteousness” is better than circumcision, which was given as a sign and was of no profit to Israel though it possessed it, we shall see that this arrogant boast has also been excluded with the greatest foresight.
(Ver. 6.) For in Christ Jesus, neither circumcision avails anything, nor uncircumcision, but faith which works by charity. For those who wish to live in Christ Jesus, virtues are to be desired, vices are to be avoided. But the things that are in between virtues and vices, neither to be avoided nor desired, such as circumcision and uncircumcision, and other similar things. Certainly, circumcision is beneficial if you keep the Law. Therefore, it was useful for those who lived under the Law, not because they were circumcised, but because the words of God were entrusted to them, which, when they turned into actions, were not foreign to salvation. And let it not move us that Sephora, taking up a stone, circumcised her son, and the angel prevented her husband from suffocating him (Exodus IV), or as it is otherwise said in Hebrew, because now circumcision is not beneficial at all, as it has testified in Christ Jesus, since the time when the Gospel has spread throughout the whole world, the injury of circumcision is unnecessary. It was valid then, like the rest of the Law, when physical blessings were promised to those who observed the Law; namely, if they fulfilled it, they would be blessed in the city, blessed in the field, have full barns, and many other things contained in the promises (Deuteronomy XXVIII). But we, in Christ Jesus, want to be strong and strengthened, that is, in true circumcision, and not in Jewish circumcision. For neither is he a Jew who is openly a Jew, nor is circumcision openly in the flesh, but he is a Jew who is hidden, and circumcision of the heart in the spirit, not in the letter (Rom. II, 28, 29). Therefore, the circumcision of the flesh is of no avail in Christ, but the circumcision of the heart and of the ears, which removes that reproach of the Jews: Behold, your ears are uncircumcised, and you cannot hear (Exod. VI, 12). The circumcision of the lips is beneficial, as Moses himself testified in Scripture: 'But I myself have foreskin on my lips.' It provides many benefits, and in matters of sexual desire, circumcision is defiled by unchastity. Therefore, in Christ Jesus, neither circumcision nor uncircumcision has any value, for they are placed in the middle, that is, between vices and virtues; but faith, which works through love, is what matters, just as the faith that was reckoned to Abraham as righteousness is confirmed, and every work of faith is placed in love, based on the whole Law and the Prophets, which depend on love. Indeed, in these two commandments: 'You shall love your God' and 'you shall love your neighbor,' the Savior asserted that the Law and the Prophets consist. And Paul in another place: 'For you shall not commit adultery, you shall not steal, you shall not covet,' and if there is any other commandment, it is summed up in this saying: 'You shall love your neighbor as yourself' (Rom. XIII, 9). Therefore, if every commandment is summed up in what has been said: 'You shall love your neighbor as yourself,' and faith works through love, it is clear that the work of faith through love contains the fullness of all the commandments. However, according to the apostle James, faith without works is dead (James 2:26): likewise, without faith, even if good works are present, they are considered dead. Therefore, those who do not believe in Christ but have good morals, what else do they possess besides the works of virtues? Let that example of faith which operates through charity be attributed to that prostitute from the Gospel, who, when she had washed the feet of the Lord while reclining at the table in the Pharisee's house, with her tears, wiped them with her hair, anointed them with ointment, and when the Pharisee murmured, the Lord presented a parable of a debtor who owed fifty and five hundred denarii, and added: For this reason, I tell you: her many sins are forgiven, for she loved much (Luke 7:47, 50). And turning to the woman, he said: Your faith has saved you, go in peace. For it has been clearly demonstrated in this place that this woman had faith through charity, which was very powerful in Christ. For who can say that circumcision in Christ is of no value, when it was known to have been valuable at one time? Did anyone ever doubt whether circumcision was circumcision? But if we consider the many Christians, that is, those of us who have been grafted onto the root of the good olive tree (Rom. 11), rejoicing against the broken branches of the Jewish people, and saying that the uncircumcised is more valuable, in which Abraham pleased God, and faith was reckoned to him for righteousness, than circumcision, which was given as a sign of faith and did not benefit those who had it, we will also see this usurpation of some now carefully excluded.
This is the faith that separates the righteous from the unclean demons, for they too, as the apostle James says, “believe and tremble,” but their actions are not good. Therefore they do not have that faith by which “the righteous live.”
If anyone, holding the faith that works through love, repents of his former sin in such as a way that he from then on turns his back on it, he will be guiltless of the blasphemy that is spoken against the Holy Spirit [namely, impenitence], which is not forgiven to the speaker either in this age or in the one to come.
[AD 220] Tertullian on Galatians 5:6