(Recapitulation.) (b) But let us look more closely at what has been said. “And certain men,” etc. In Jerusalem, then, there were not any believers from among the Gentiles: but in Antioch of course there were. Therefore there came down certain yet laboring under this disease of the love of rule, and wishing to have those of the Gentiles attached to them. And yet Paul, though he too was learned in the Law, was not thus affected. “When therefore Paul and Barnabas had no small disputation with them,” etc. But when he returned from thence, the doctrine also became more exact. For if they at Jerusalem enjoin no such thing, much more these (have no right to do so). “And being brought on their way,” etc, “they caused no small joy to the brethren.” Do you mark, as many as are not enamoured of rule, rejoiced in their believing? It was no ambitious feeling that prompted their recitals, neither was it for display, but in justification of the preaching to the Gentiles. Thus they say nothing of what had happened in the matter of the Jews. “But there arose up certain of the sect of the Pharisees which believed,” etc. (a) But even if they would needs bring over the Gentiles to their side, they learn that neither must the Apostles overlook it. “And the Apostles and elders,” etc. “Among us,” he says, “God chose:” and “from old days:” long ago, he says, not now. And this too is no small point— at a time when Jews believed, not turned away (from the Gospel). “Among us;” an argument from the place: “of old days,” from the time. And that expression, “Chose:” just as in their own case he says not, (so) willed it, but, “Chose that the Gentiles by my mouth should hear the word of the Gospel and believe.” Whence is this proved? From the Spirit. Then he shows that the testimony given them is not of grace merely, but of their virtue. “And God which knows the hearts bare them witness”; having afforded to them nothing less (than to us), for, he says, “Put no difference between us and them.” Why then, hearts are what one must everywhere look to. And it is very appositely said, “God that knows the hearts bare them witness:” as in the former instance, “You, Lord, that know the hearts of all men.” For to show that this is the meaning, observe what he adds, “Put no difference between us and them.” When he has mentioned the testimony borne to them, then he utters that great word, the same which Paul speaks, “Neither circumcision avails anything, nor uncircumcision.” “That he may make the two one in Himself.” Of all these the seeds lie in Peter's discourse. And he does not say (between) them of the circumcision, but “Between us,” that is the Apostles, “and them.” Then, that the expression, “no difference” may not seem an outrage, After faith, he says— “Having purified their hearts by faith” — He thoroughly cleansed them first. Then he shows, not that the Law was evil, but themselves weak.— “But we believe that through the grace of the Lord Jesus we shall be saved even as they.” Mark how he ends with a fearful consideration. He does not discourse to them from the Prophets, but from things present, of which themselves were witnesses. Of course (the Prophets) also themselves anon add their testimony (infra v. 15), and make the reason stronger by what has now come to pass. And observe, he first permits the question to be moved in the Church, and then speaks. “And put no difference between”— he said not, them of the circumcision, but “us and them,” i.e. the Gentiles: for this (gradual advance) little by little is stronger. “Why therefore do you tempt God?” who has become (the) God of the Gentiles: for this was tempting: * * * whether He is able to save even after the Law. See what he does. He shows that they are in danger. For if, what the Law could not do, faith had power to do, “we believe that through the grace of the Lord Jesus we shall be saved even as they”: but faith falling off, behold, themselves (are) in destruction. And he did not say, Why do ye disbelieve? Which was more harsh, but, “Tempt God,” and that when the fact is demonstrated.
(c) Great effrontery this, of the Pharisees, that even after faith they set up the Law, and will not obey the Apostles. But see these, how mildly they speak, and not in the tone of authority: such words are amiable, and more apt to fix themselves in the mind. Observe, it is nowhere a display of words, but demonstration by facts, by the Spirit. And yet, though they have such proofs, they still speak gently. And observe they do not come accusing those at Antioch, but “declaring all things that God had done with them:” but thence again these men lay hold upon the occasion (to compass their own objects), “but there rose up,” etc. Such were the pains they took in their love of power: and it was not with the knowledge of the Apostles that they Paul and Barnabas were blamed. But still they brought forward none of these charges: but when they have proved the matter, then (the Apostles) write in stronger terms.
Source: Homilies on Acts (New Advent)