Our Old Testament is a history of God's dealings with a chosen people who were to be light and salt in the world. However, they failed, becoming as broken as the world around them. God's faithfulness, though, is demonstrated through His son Jesus Christ, who came to earth as the perfect fulfilment of Israel's mandate...(in effect, God fulfilled Israel's side of the covenant through Jesus- the perfect man, perfect Jew, perfect ambassador of God.) Romans 9 through 11 is the most comprehensive account of God's dealings with the Jews in the New Testament.
In a nutshell- God has temporarily turned from Israel because of their rejection of Christ. This has made the way for the Gentiles(non-Jews) to be ushered into the same calling to be ambassadors of His Sovereign Reigning Power in the earth. God's selection of the Gentiles is expressed as a potter choosing to make a vessel for honour or dishonour- at their rejection of Christ, Israel became a vessel of dishonour in order that the fullness of the Gentiles might rush into the Kingdom of God and in so doing provoke the Jews to also come and experience the fullness of life in the Spirit -free from the bondage of the law and sin!
Paul wants us to avoid thinking the Church has replaced Israel, but that it is grafted into Israel. We are now partakers of all the blessings of the Old Testament promises. We are ushered into that family though we may or may not share Jewish DNA. What then should be our response?
I think there are two responses for us...
1. We must develop a prayerful heart toward Israel. Perhaps whenever you hear of Israel in the news let it be a pointer to pray Paul's prayer- that they might be saved! Romans 10:1
2. Let us live in the awareness of our calling to be fruitful in this world and not take salvation for granted. It is our living faith in Jesus Christ that sustains our connection with God and we do not want to dry up into the shameful position of potentially being 'snapped off' because of fruitlessness! Romans 11:22