Romans 9:26

And it shall be, in the place where it was said unto them, Ye are not my people, There shall they be called sons of the living God.

This prophecy is also from Hosea (Hosea 1:10) and is a clear promise of the coming of the Gentiles into the relationship with God as "sons." Hosea made this development to lie in the future, as it indeed was when he wrote; but under the preaching of the gospel this had already begun to be fulfilled, the letter to the Romans itself being proof that Gentiles were indeed called "sons of God," thus making them to share in the highest and holiest blessing life on earth has ever afforded. How incredible it seems that Israel's leaders did not heed these prophecies, nor even the fulfillment of them taking place at that moment before their eyes! But Paul was by no means finished; he would pile prophecy upon prophecy.