God promised Abraham that in him all the nations of the earth would be blessed. That promise was not fulfilled in the Jews as a people but in the person of Jesus Christ. All who believe in Jesus are children of Abraham, and are heirs together with faithful Jews as “the Israel of God” (Galatians 6:16).
It is a mistake to think of this “people group” as either Jewish or non-Jewish, or as a mingling of both. Spiritual Israel is “neither Jew nor Gentile” because all are one in [union with] Jesus Christ. What then of Abraham’s natural descendants? “They are beloved for the sake of Abraham, Isaac and Jacob — the “fathers” or patriarchs of the Hebrew people. “The gifts and the calling of God are irrevocable” (Romans 11:29).
I once thought that in chapters 9 to 11 of Romans Paul drifted away from his subject, which peaked at the end of chapter 8 with the inability of anything to separate us from the love of God in Jesus our Lord.
I came to see that the three chapters record in detail the mercy of God His dealings with Israel, while allowing non-Jewish believers to share the Abrahamic faith knows as Christianity. Through the Cross of Jesus, the once exclusive Hebrew faith became inclusive of believers from all nations, peoples, tribes and languages. “Whoever will may [now] take of the water of life and [drink] freely.” The gift of God’s Spirit is for every believer.
No wonder that Romans, chapter 11, ends with a thrilling doxology on the wisdom and mercy of God, one that segues perfectly into the beginning of chapter 12 and the Apostle Paul’s plea for our response to that mercy, as described in such detail in chapters 9 to 11.