In the eleventh chapter of Romans, where the apostle is showing that Israel's present "blindness" is not to continue for ever, he declares, "I say then, Have they stumbled that they should fall? God forbid: but rather through their fall salvation is come unto the Gentiles, for to provoke them to jealousy. Now if the fall of them (Israel) be the riches of the world (i.e., the enrichment of the Gentiles by the Gospel), and the diminishing of them the riches of the Gentiles; how much more their fullness? (that is, How much more will Israel's latter-day blessing enrich the Gentiles). For if the casting away of them be the reconciling of the world, what shall the receiving of them be, but life from the dead?" (vss.11, 12, 15). How clear it is from these verses that, universal blessings for mankind are not to be brought about by the indefinite prolongation of this present dispensation and the preaching of the Gospel, but by the restoration of Israel, after Christendom has been cut off for its non-continuance in God's goodness. As another has said, "The end of apostate Judaism was judgment: the end of apostate Gentile Christianity will be judgment also. But just as blessing came to us when judgment fell upon the Jew, so when judgment falls upon Christendom, blessing will be restored to Israel, and Israel's restoration will bring still fuller blessing to the world than any it has had during the present dispensation; it will be as "life from the dead!" (W. Trotter).
The words of Simeon recorded in Acts 15 are in perfect agreement with the teaching of Romans 11 -- "Simeon hath declared how God at the first did visit the Gentiles to take out of them a people for His name. And to this agree the words of the prophets; as it is written, after this, I will return, and will build again the tabernacle of David (i. e., Israel), which is fallen down; and I will build again the ruins thereof, and I will set it up; that the residue of men might seek after the Lord, and all the Gentiles, upon whom My name is called, saith the Lord, who doeth all these things" (vss.14-17). It is to be noted that here again the "seeking of the Lord" by the "residue of men and all the Gentiles" is subsequent to the restoration of Israel.
There are many prophecies in the Old Testament which speak of the Millennial blessedness of the Gentiles. We single out one or two without commenting extensively upon them. "And the glory of the Lord shall be revealed, and all flesh shall see it together: for the mouth of the Lord hath spoken it" (Is.40:5). "O sing unto the Lord a new song; for He hath done marvelous things: His right hand, and His holy arm, hath gotten Him the victory. The Lord hath made known His salvation: His righteousness hath He openly shewed in the sight of the heathen. He hath remembered His mercy and His truth toward the house of Israel: all the ends of the earth have seen the salvation of our God" (Ps.98:1-3). Once more the order is the same: God's righteousness is displayed before the "heathen" and His salvation is made known to the ends of the earth following God's dealing in mercy with Israel.
One more quotation must suffice: "And ye shall know that I am in the midst of Israel, and that I am the Lord your God, and none else: and My people shall never be ashamed. And it shall come to pass afterward, that I will pour out My Spirit upon all flesh"(Joel 2:27, 28). Like all prophecy, this one receives a double fulfillment. It is to be observed that when Peter quoted from Joel on the Day of Pentecost he did not say, "And now is fulfilled that which was spoken by the prophet Joel" (Acts 2:16), because the words of Joel quoted above will not be filled until the Millennium, then and not till then, will God's Spirit be poured out upon "all flesh" -- for that glad day, the earth waits the Second Advent of our Lord. Thus we see that the Return of Christ to this earth to usher in the Millennium will be attended with gracious and wide blessing to the Gentiles, for then it will be that "The earth shall be full of the knowledge of the glory of the Lord as the waters cover the sea" (Is.11:9). Again, the Return of the Redeemer is a Blessed Hope.