What he means is somewhat as follows. Pharaoh was a vessel of wrath, that is, a man who by his own hard-heartedness had kindled the wrath of God. For after enjoying much long-suffering, he became no better, but remained unimproved. Wherefore he calls him not only "a vessel of wrath," but also one "fitted for destruction." That is, fully fitted indeed, but by his own proper self. For neither had God left out anything of the things likely to recover him, nor did he leave out anything of those that would ruin him, and put him beyond any forgiveness. Yet still, though God knew this, "He endured him with much long-suffering," being willing to bring him to repentance. For had He not willed this, then He would not have been thus long-suffering. But as he would not use the long-suffering in order to repentance, but fully fitted himself for wrath, He used him for the correction of others, through the punishment inflicted upon him making them better, and in this way setting forth His power. For that it is not God's wish that His power be so made known, but in another way, by His benefits, namely, and kindnesses, he had shown above in all possible ways. For if Paul does not wish to appear powerful in this way ("not that we should appear approved," he says, "but that you should do that which is honest,") [2 Corinthians 13:7], much less does God. But after that he had shown long-suffering, that He might lead to repentance, but he did not repent, He suffered him a long time, that He might display at once His goodness and His power, even if that man were not minded to gain anything from this great long-suffering. As then by punishing this man, who continued incorrigible, He showed His power, so by having pitied those who had done many sins but repented, He manifested His love toward man. But it does not say, love towards man, but glory, to show that this is especially God's glory, and for this He was above all things earnest. But in saying, "which He had afore prepared unto glory," he does not mean that all is God's doing. Since if this were so, there were nothing to hinder all men from being saved. But he is setting forth again His foreknowledge, and doing away with the difference between the Jews and the Gentiles. And on this topic again he grounds a defense of his statement, which is no small one. For it was not in the case of the Jews only that some men perished, and some were saved, but with the Gentiles also this was the case. Wherefore he does not say, all the Gentiles, but, "of the Gentiles," nor, all the Jews, but, "of the Jews." As then Pharaoh became a vessel of wrath by his own lawlessness, so did these become vessels of mercy by their own readiness to obey. For though the more part is of God, still they also have contributed themselves some little. Whence he does not say either, vessels of well-doing, or vessels of boldness (παρρησίας), but "vessels of mercy," to show that the whole is of God. For the phrase, "it is not of him that wills, nor of him that runs," even if it comes in the course of the objection, still, were it said by Paul, would create no difficulty. Because when he says, "it is not of him that wills, nor of him that runs," he does not deprive us of free-will, but shows that all is not one's own, for that it requires grace from above. For it is binding on us to will, and also to run: but to confide not in our own labors, but in the love of God toward man. And this he has expressed elsewhere. "Yet not I, but the grace which was with me." [1 Corinthians 15:10] And he well says, "Which He had afore prepared unto glory." For since they reproached them with this, that they were saved by grace, and thought to make them ashamed, he far more than sets aside this insinuation. For if the thing brought glory even to God, much more to them through whom God was glorified. But observe his forbearance, and unspeakable wisdom. For when he had it in his power to adduce, as an instance of those punished, not Pharaoh, but such of the Jews as had sinned, and so make his discourse much clearer, and show that where there were the same fathers, and the same sins, some perished, and some had mercy shown them, and persuade them not to be doubtful-minded, even if some of the Gentiles were saved, while the Jews were perishing; that he might not make his discourse irksome, the showing forth of the punishment he draws from the foreigner, so that he may not be forced to call them "vessels of wrath." But those that obtained mercy he draws from the people of the Jews. And besides, he also has spoken in a sufficient way in God's behalf, because though He knew very well that the nation was fitting itself as a vessel of destruction, still He contributed all on His part, His patience, His long-suffering, and that not merely long-suffering, but "much long-suffering;" yet still he was not minded to state it barely against the Jews. Whence then are some vessels of wrath, and some of mercy? Of their own free choice. God, however, being very good, shows the same kindness to both. For it was not those in a state of salvation only to whom He showed mercy, but also Pharaoh, as far as His part went. For of the same long-suffering, both they and he had the advantage. And if he was not saved, it was quite owing to his own will: since, as for what concerns God, he had as much done for him as they who were saved. Having then given to the question that answer which was furnished by facts, in order to give his discourse the advantage of other testimony in its favor, he introduces the prophets also making the same declarations aforetime. For Hosea, he says, of old put this in writing, as follows:
What is more worthy than to magnify the ministry which one has received by the providence of God? For the man who ministers well magnifies his ministry, while on the other hand the one who has ministered negligently and unworthily dishonors his ministry and draws unfavorable comment on it.
Paul is showing the Gentiles here how much he loves the Jews. For he magnifies his ministry, by which he is the apostle of the Gentiles, if by loving his own people he wins them to the faith as well. For he is more honored still if he wins to eternal life those to whom he has not been sent. For he who finds his lost brothers will have the greatest honor with his parents.
Again he endeavors much to get himself clear of untoward suspicion. And he seems to be blaming the Gentiles, and to be humbling their conceits, yet he gives a gentle provocation to the Jew also. And indeed he goes round about seeking to veil and allay this great ruin of theirs. But he finds no means of doing it, owing to the nature of the facts. For from what he had said, they deserved but the greater condemnation, when those who were far short of them had taken the good things prepared for them. This is why then he passes from the Jews to those of the Gentiles, and puts in between his discourse the part about them, as wishing to show that he is saying all these things in order to instruct them to be reasonable. For I praise you, he means, for these two reasons; one, because I am necessitated to do so as being your commissioned minister; the other, that through you I may save others. And he does not say, my brethren, my kinsmen; but, "my flesh." And next, when pointing out their disputatious spirit, he does not say, "if by any means I may" persuade, but, "provoke to jealousy and save;" and here again not all, but, "some of them." So hard were they! And even amid his rebuke he shows again the Gentiles honored, for they are causes of their salvation, and not in the same way. For they became purveyors of blessings to them through unbelief, but these to the Jews by faith. Hence the estate of the Gentiles seems to be at once equal and superior. For what will you say, O Jew? That if we had not been cast out, he would not have been called so soon? This the man of the Gentiles may say too, If I had not been saved, you would not have been moved to jealousy. But if you would know wherein we have the advantage, I save you by believing, but it is by stumbling that you have afforded us an access before yourself. Then perceiving again that he had touched them to the quick, resuming his former argument, he says,
Paul wants to show that he is especially anxious to save the Jews. As long as he is in the body he will honor his ministry, striving to save many of them by his example.
[AD 407] John Chrysostom on Romans 9:22-23:24