"I extend the word Israel to all the people of God, according to this meaning, When the Gentiles shall come in, the Jews also shall return from their defection to the obedience of faith; and thus shall be completed the salvation of the whole Israel of God, which must be gathered from both; and yet in such a way that the Jews shall obtain the first place, being as it were the first born in God's family.
...as Jews are the firstborn, what the Prophet declares must be fulfilled, especially in them: for that scripture calls all the people of God Israelites, it is to be ascribed to the pre-eminence of that nation, who God had preferred to all other nations...God distinctly claims for himself a certain seed, so that his redemption may be effectual in his elect and peculiar nation...God was not unmindful of the covenant which he had made with their fathers, and by which he testified that according to his eternal purpose he loved that nation: and this he confirms by this remarkable declaration, that the grace of the divine calling cannot be made void."
(see Calvin's Commentaries, Vol. XIX, Epistle to the Romans, Baker Book House, 1981, p. 434-440.)
"The second great event, which, according to the common faith of the Church, is to precede the second advent of Christ, is the national conversion of the Jews....that there is to be such a national conversion may be argued...from the original call and destination of that people. God called Abraham and promised that through him, and in his seed, all the nations of the earth should be blessed...A presumptive argument is drawn from the strange preservation of the Jews through so many centuries as a distinct people.
As the rejection of the Jews was not total, so neither is it final. First, God did not design to cast away his people entirely, but by their rejection, in the first place, to facilitate the progress of the gospel among the Gentiles, and ultimately to make the conversion of the Gentiles the means of converting the Jews...Because if the rejection of the Jews has been a source of blessing, much more will their restoration be the means of good...The restoration of the Jews to the privileges of God's people is included in the ancient predictions and promises made respecting them...The plan of God, therefore, contemplated the calling of the Gentiles, the temporary rejection and final restoration of the Jews...
The future restoration of the Jews is, in itself, a more probable event than the introduction of the Gentiles into the church of God. This, of course, supposes that God regarded the Jews, on account of their relation to him, with peculiar favor, and that there is still something in their relation to the ancient servants of God and his covenant with them, which causes them to be regarded with special interest. As men look upon the children of their early friends with kinder feelings than on the children of strangers, God refers to this fact to make us sensible that he still retains purposes of peculiar mercy towards his ancient people.
As the restoration of the Jews is not only a most desirable event, but one which God has determined to accomplish, Christians should keep it constantly in view even in their labors for the conversion of the Gentiles."
(Systematic Theology V.3, James Clark & Co. 1960, p. 805. and A Commentary on the Epistle to the Romans, Presb. Board of Pub., 1836, pp. 270-285 passim. Now Published by Banner of Truth Trust)
"To the Jew first, and also to the Greek...It does not appear sufficient to regard this priority as that merely of time. In this text there is no suggestion to the effect that the priority is merely that of time. The implication appears to be rather that the power of God unto salvation through faith has primary relevance to the Jew, and the analogy of Scripture would indicate that this peculiar relevance to the Jew arises from the fact that the Jew had been chosen by God to be the recipient of the promise of the gospel and that to him were committed the oracles of God...the gospel is pre-eminently the gospel for the Jew.
While it is true that in respect of the privileges accruing from Christ's accomplishments there is now no longer Jew or Gentile and the Gentiles "are fellow-heirs, and fellow-members of the body, and fellow-partakers of the promise in Christ Jesus through the gospel" (Eph. 3:6), yet it does not follow that Israel no longer fulfills any particular design in the realization of God's worldwide saving purpose...Israel are both "enemies" and "beloved" at the same time, enemies as regards the gospel, beloved as regards the election..."Beloved" thus means that God has not suspended or rescinded his relation to Israel as his chosen people in terms of the covenants made with their fathers.
Unfaithful as Israel have been and broken off for that reason, yet God still sustains his peculiar relation of love to them, a relation that will be demonstrated and vindicated in the restoration."
(The Epistle to the Romans, John Murray, Wm. B. Eerdmans Pub. Co., 1984, Vol. I, p. 28 and Vol. II pp. xiv-xv and 76-101, passim.)
"Jewish infidelity shall be overthrown...the Jews in all their dispersions shall cast away their old infidelity, and shall have their hearts wonderfully changed, and abhor themselves for their past unbelief and obstinacy. They shall flow together to the blessed Jesus, penitently, humbly, and joyfully owning him as their glorious King and only Savior, and shall with all their hearts, as one heart and voice, declare his praises unto other nations...Nothing is more certainly foretold than this national conversion of the Jews in Rom. xi.
Besides the prophecies of the calling of the Jews, we have a remarkable providential seal of the fulfillment of this great event, by a kind of continual miracle, viz. their being preserved a distinct nation...the world affords nothing else like it. There is undoubtedly a remarkable hand of providence in it. When they shall be called, that ancient people, who alone were so long God's people for so long a time, shall be his people again, never to be rejected more. They shall be gathered together into one fold, together with the Gentiles...."
(The Works of Jonathan Edwards, Volume 1, Banner of Truth Trust, 1976, page 607.)
"Now two things he exhorts the Gentiles to, with reference to the rejected Jews: To have a respect for the Jews, notwithstanding, and to desire their conversion. This is intimated in the prospect he gives them of the advantage that would accrue to the church by their conversion, Rom. 11:12, 15. It would be as life from the dead; and therefore they must not insult or triumph over those poor Jews, but rather pity them, and desire their welfare, and long for the receiving of them in again.
Another thing that qualifies this doctrine of the Jews' rejection is that, though for the present they are cast off, yet the rejection is not final; but, when the fullness of time is come, they will be taken in again. They are not cast off for ever, but mercy is remembered in the midst of wrath.
The Jews are in a sense a holy nation (Exod. xix.6), being descended from holy parents. Now it cannot be imagined that such a holy nation should be totally and finally cast off. This proves that the seed of believers, as such, are within the pale of the visible church, and within the verge of the covenant, till they do, by their unbelief, throw themselves out; for, if the root be holy, so are the branches....Though grace does not run in the blood, yet external privileges do (till they are forfeited), even to a thousand generations...The Jewish branches are reckoned holy, because the root was so. This is expressed more plainly (Rom. 11:28).
Though particular persons and generations wear off in belief, yet there having been a national church-membership, though for the present suspended, we may expect that it will be revived...It is called a mystery (Rom. 11:25), that which was not obvious, and which one would not expect upon the view of the present state of that people, who appeared generally so obstinate against Christ and Christianity that it was a riddle to talk of their unanimous conversion. Alas! who shall live when God doeth this?"
(Matthew Henry's Commentary, V.6, MacDonald Publishing Company, pp. 448-453.)