After all the excitement of chapter 8, why does Paul turn to consideration of his fellow Jews in chapter 9? Is it because of his grief over their rejection of the salvation which he has found? This is part of it. But there is a more pressing question which is of great import for all of us: does God keep his promises? God made many promises to Israel, yet now Israel had rejected God and God has seemingly rejected Israel. Might this also mean that God could also reject Christians, the new people of God? (Olyott, p. 113)
God has not rejected any of his promises nor will he ever. The key to resolving the apparent tension is understanding the difference between earthly Israel and true Israel. Look at v. 6: “It is not as though God’s word had failed. For not all who are descended from Israel are Israel.”
As believers, we can be assured that God will keep his promises to us, just as we can be assured that he has and will keep his promises to Israel. Developing a deeper understanding of both of these things means paying close attention to Paul’s train of thought as it unfolds from chapter 9 through chapter 11. Stay tuned.