“I am speaking the truth in Christ–I am not lying; my conscience bears me witness in the Holy Spirit–that I have great sorrow and unceasing anguish in my heart. For I could wish that I myself were accursed and cut off from Christ for the sake of my brothers, my kinsmen according to the flesh.” (Romans 9:1-5)
Paul confessed that Jewish unbelief has caused him anguish. He wondered how the chosen people could have rejected their own Messiah. They were, after all, the people to whom He had chosen to reveal Himself, and, through them, to the rest of the people of the world. God had worked mighty miracles among them, a testimony of His power and sovereignty. They should have known better.
Paul wondered if the rejection of Jesus by the Jews meant that somehow God has gone back on His promises, that He has acted contrary to His own nature. But Paul realized that God’s promises were not to national or ethnic Israel, but to the true, spiritual Israel. Just because a person was born a Jew and circumcised, this did not mean he was a member of this true Israel. Of course, there was a remnant of Jews who had accepted Christ. Yet the majority had rejected Him, choosing rather to pursue their own righteousness, prideful in their assumption that either they could keep the law to perfection or else resting in their national heritage as the chosen people assured of their righteous standing before the Lord no matter how they lived.
Paul maintained that the true elect of God come from both Jews and Gentiles. He has shown mercy toward those whom He has chosen, not because of anything they had done but out of His love and of His own sovereign will. On the other hand He promises judgment and condemnation on those who reject Him. Thus the fact that who have heard the gospel yet still reject Jesus should sadden us as well. They have hardened their hearts against Him. God will grant them what they want and deserve, eternal punishment separated from Him and His love forever. If only they would turn to Him and believe.