Romans 11:31

"According to the Gospel indeed they are enemies for your sake: but according to the election they are most dear for the sake of the fathers. For the gifts and the calling of God are without repentance. For as you also once did not believe God, but now have obtained mercy because of their unbelief: so these also have now not believed, that through the mercy shown to you they too may obtain mercy." The Apostle, still pursuing the same matters concerning Israel and the Gentiles, and reproaching the branches of the wild olive which insulted the broken branches of the olive tree, adds also these things: That Israel according to the Gospel has indeed been made an enemy to God, because it did not believe Christ: but so far as regards the honor due to the fathers, it is elect, and is held most dear with God. But election having once been granted to the seed of the fathers, and love conceded, God without doubt preserves his gifts and his calling toward the seed of those to whose merits he once bestowed this: nor does repentance come upon God, even if those upon whom the benefits promised to the fathers are conferred appear to be less worthy. But, as we have often advised, in the present passage also that distinction is to be observed, that the Israel which is an enemy to God is said to be that which cries out concerning Christ: "Away with him, away with him, crucify him." For how should they not be called enemies of God, who either then, or even now, have said such things, or say them? But when he says, "for your sake," this means, those namely whose salvation they envy, forbidding the apostles to speak to the Gentiles, and persecuting those who announce Christ. But according to the remnant which is said to be saved, in which the election of believers followed from Israel, they are "most dear for the sake of the fathers:" whose faith namely they follow, believing "in him who raised Christ Jesus from the dead." And according to this, toward such a seed "the gifts and the calling of God are without repentance." But after these things he opens also the hidden and deeper causes of their unbelief, and says: That just as you Gentiles once did not believe God, nor yet did God on that account utterly abandon you, but at last at some time you obtained mercy — yet the occasion of mercy being conferred upon you was the unbelief of the people of Israel — so also these who now from the people of Israel have not believed, and for their unbelief have been abandoned, so that the mercy of God might be turned toward you, will not be left forever in their unbelief; but after the dispensation of the fullness of the Gentiles has been fulfilled, they too shall obtain mercy.

Paul recalls the unbelief of the Gentiles so that being ashamed of it they may not insult the Jews who have not believed but rejoice when they accept the promise of God.

"For as ye in times past have not believed God, yet have now obtained mercy through their unbelief; even so have these also now not believed, that through your mercy they may also obtain mercy. For God hath concluded them all in unbelief, that He might have mercy upon all."

He shows here that those of the Gentiles were called first. Then, as they would not come, the Jews were elected, and the same result occurred again. For when the Jews would not believe, again the Gentiles were brought over. And he does not stop here, nor does he draw the whole to a conclusion at their rejection, but at their having mercy shown them again. See how much he gives to those of the Gentiles, as much as he did to the Jews before. For when ye, he would say, "in times past did not obey," being of the Gentiles, then the Jews came in. Again, when these did not obey, ye have come. However, they will not perish forever. "For God hath concluded them all in unbelief," that is, hath convinced them, hath shown them disobedient; not that they may remain in disobedience, but that He may save the one by the captiousness of the other, these by those and those by these. Now consider; ye were disobedient, and they were saved. Again, they have been disobedient, and ye have been saved. Yet ye have not been so saved as to be put away again, as the Jews were, but so as to draw them over through jealousy while ye abide.

Christ is the mercy of the Gentiles. They have been such unbelievers that they too are justified not by their works but in mercy, as you are.

[Daniel 2:22] "It is He who reveals deep and hidden things, and He knows what is placed in the darkness, and with Him is the light." A man to whom God makes profound revelations and who can say, "O the depth of the riches of the knowledge and wisdom of God!" (Romans 11:33), he it is who by the indwelling Spirit probes even into the deep things of God, and digs the deepest of wells in the depths of his soul. He is a man who has stirred up the whole earth, which is wont to conceal the deep waters, and he observes the command of God, saying: "Drink water from thy vessels and from the spring of thy wells" (Proverbs 5:15). As for the words which follow, "He knows what is placed in the darkness, and with Him is the light," the darkness signifies ignorance, and the light signifies knowledge and learning. Therefore as wrong cannot hide God away, so right encompasses and surrounds Him. Or else we should interpret the words to mean all the dark mysteries and deep things (concerning God), according to what we read in Proverbs: "He understands also the parable and the dark saying." (Proverbs 1:6, LXX) This in turn is equivalent to what we read in the Psalms: "Dark waters in the clouds of the sky" (Psalm 18:11). For one who ascends to the heights and forsakes the things of earth, and like the birds themselves seeks after the most rarified atmosphere and everything ethereal, he becomes like a cloud to which the truth of God penetrates and which habitually showers rain upon the saints. Replete with a plenitude of knowledge, he contains in his breast many dark waters enveloped with deep darkness, a darkness which only Moses can penetrate and speak with God face to face (Exodus 33:11), of Whom the Scripture says: "He hath made darkness His hiding-place" (Psalm 18:11).

But the mercy shown to you will also be their mercy: they will emulate you and believe, and thus will be deemed worthy of your mercy.

So these also, i.e., the Jews, now, i.e., in the time of grace, have not believed, namely, in Christ: why do you not believe in me? (John 8:46). And this is what he adds: for your mercy, i.e., in Christ's grace, by which you have obtained mercy: you have saved us according to your mercy (Titus 3:5). Or they have not believed so that they might enter into your mercy. Or they have not believed, which turned out to be the occasion of the mercy shown to you, that they also at some time may obtain mercy: the Lord will have compassion on Jacob (Isa 14:1).