The Hope of Jews and Gentiles
"For I tell you that Christ became a servant to the circumcised to show God's truthfulness, in order to confirm the promises given to the patriarchs, and in order that the Gentiles might glorify God for his mercy" (vv. 8-9a).
Paul's exhortation for mature Christians and weak, or immature, believers to welcome one another and not divide over nonessential matters was prompted by divisions between Jews and Gentiles in the Roman church (Rom. 14:1-15:7). The strong, mature believers knew that they were free to eat whatever is sanctified by prayer. But the weak, immature believers had not yet grasped the truth of their freedom in the Lord. Remembering this background explains why the Apostle can move from a discussion of Christian freedom to Jesus' fulfillment of God's promises to Jews and Gentiles in today's passage.
We have already seen that believers are to receive one another even when they disagree on minor issues, because God in Christ has received believers on both sides of nonessential matters (14:3; 15:7). In Romans 15:8-12, Paul gives additional theological justification for Christians to welcome one another by reminding his readers of God's purpose to bring Jews and Gentiles together in the worship of the one, true Creator—Yahweh, the covenant Lord of Israel. Paul looks back to the patriarchs, stating that Christ came as a "servant to the circumcised"—to Jews—to confirm the promises made to Abraham, Isaac, and Jacob. In stating that Jesus was a servant to Jews, Paul does not mean that Jewish Christians are masters over Jesus; rather, his point is that the Son of God came to meet the needs of His people, to serve them at the deepest level possible in saving them from sin.
What were the promises given to the patriarchs? Genesis 12:1-3 gives the core promises, which are elaborated throughout the rest of God's dealings with Abraham and his sons. These promises consist of a good land, a great name, and many children for Abraham, but all of these were given with the intention that Abraham's family would become a blessing to all the families of the earth. By coming to meet the needs of the Jews for salvation, Jesus confirmed that Abraham's family according to the flesh blesses the whole world, for salvation for the Gentiles comes through the Jewish Messiah born to the Jewish people.
Because salvation comes to the Gentiles through the Jewish people on account of Christ, Jesus also became a servant in order that the Gentiles—non-Jews—would glorify God for His mercy in saving them (Rom. 15:8-9a). Christ's work brings together Jew and Gentile as one people deeply grateful for their redemption.
Coram Deo
Christ came to meet the needs of His people, to humble Himself and do whatever was necessary to redeem us from our bondage to sin. He did this without respect to ethnicity, which means that we are to welcome all who trust in Christ alone no matter their background. Jesus has confirmed the promises to the patriarchs, and therefore we are to seek unity among all Christians of every nationality, unity that is grounded in the truth of our Lord's person and work.