8 (According as it is written, God hath given them the spirit of slumber, eyes that they should not see, and ears that they should not hear;) unto this day.
[AD 407] John Chrysostom on Romans 9:22-23:24
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:

[AD 253] Origen of Alexandria on Romans 11:8
I have not been able to find the source of this quotation. If someone consults holy Scripture more carefully than I have done and finds it, let him say so.

[AD 382] Apollinaris of Laodicea on Romans 11:8
This quotation was taken directly from the Hebrew by the apostle himself. The Septuagint edition has “God has put a spirit of stupor in you.” The version of Aquila more clearly has “virulence” and that of Symmachus has “pride.” … In effect, because of the ignorance of the people, the prophetic writings will be a sealed book to them, and they will be incapable of reading them.

[AD 384] Ambrosiaster on Romans 11:8
These are the carnal Israelites who thought they were justified by the law and did not realize that they were justified by faith before God, because through the law they were all guilty.Those who were blinded were those who were unable to see the way of truth which in their wickedness they had rejected and gone away from so that they could no longer come to the grace of salvation. The examples taken from the prophets reveal that there are two kinds of blind people. The first kind consists of those who are blinded forever, who will never be saved. These people are of such evil will that they knowingly say that they do not know what they hear.… The second type consists of those who, although they try to live according to the law, do not accept the righteousness of Christ. These people are doing this not out of the envy of an evil will but by an erroneous imitation of the tradition of their ancestors. They are blinded for a time, for although they ought to recognize the great works of Christ which cannot be ignored.… They have forgotten God and follow human opinions instead.

[AD 407] John Chrysostom on Romans 11:8
Or rather we should go back to the beginning of his argument. Having then mentioned the state of things in Elijah's time, and shown what grace is, he proceeds, "What then? Israel has not obtained that which he seeks for." Now this is as much what an accuser would say, as what one who was putting a question. For the Jew, he means, is inconsistent with himself when he seeks for righteousness, which he will not accept. Then to leave them with no excuse, he shows, from those who have accepted it, their unfeeling spirit, as he says, "But the election has obtained it," and they are the condemnation of the others. And this is what Christ says, "But if I by Beelzebub cast out devils, by whom do your children cast them out? Wherefore they shall be your judges." [Luke 11:19] For to prevent any one from accusing the nature of the thing, and not their own temper, he points out those who had obtained it. Hence he uses the word with great propriety, to show at once the grace from above and the zeal of these. For it is not to deny free-will that he speaks of their having "obtained" (as by chance, Gr. ἐ πέτυχε) it, but to show the greatness of the good things, and that the greater part was of grace, though not the whole. For we too are in the habit of saying, "so and so chanced to get" (same word), "so and so met with," when the gain has been a great one. Because it is not by man's labors, but by God's gift, that the greater part was brought about.

"And the rest was blinded."

See how he has been bold enough to tell with his own voice the casting off of the rest. For he had indeed spoken of it already, but it was by bringing the prophets in as accusers. But from this point he declares it in his own person. Still even here he is not content with his own declaration, but brings Isaiah the prophet in again. For after saying, "were blinded," he proceeds; "according as it is written, God has given them the spirit of slumber." Now whence came this blinding? He had indeed mentioned the causes of it before, and turned it all upon their own heads, to show that it was from their unseasonable obstinacy that they had to bear this. And now he speaks of it too. For when he says, "Eyes that they should not see, and ears that they should not hear," he is but finding fault with their contentious spirit. For when they had "eyes to see" the miracles, and were possessed of "ears to hear" that marvellous Teaching, they never used these as were fitting. And the "He gave," do not imagine to mean here an agency, but a permission only. But "slumber" (καταάνυξις] lit. piercing) is a name he here gives to the habit of soul inclinable to the worse, when incurably and unchangeably so. For in another passage David says, "that my glory may sing unto You, and I may not be put to slumber" [Psalm 30:12, Septuagint]: that is, I may not alter, may not be changed. For as a man who is hushed to slumber in a state of pious fear would not easily be made to change his side; so too he that is slumbering in wickedness would not change with facility. For to be hushed to slumber here is nothing else but to be fixed and riveted to a thing. In pointing then to the incurable and unchangeable character of their spirit, he calls it "a spirit of slumber." Then to show that for this unbelief they will be most severely punished, he brings the Prophet forward again, threatening the very things which in the event came to pass.

[AD 418] Pelagius on Romans 11:8
The rest were hardened through unfaithfulness, as it is written: “Unless you believe, you will not understand.”It is God’s prerogative to give them the spirit of stupor which they desired, for they have always disbelieved the words of God. If they had wanted to have a spirit of faith they would have received it. But even today Christians who doubt the resurrection reward or Gehenna have sought a similar spirit for themselves, for in this passage the prophet was addressing both believers and sinners.

[AD 471] Gennadius of Constantinople on Romans 11:8
The spirit of stupor prevented them from making the hard choice of repentance and conversion.