Part III — The New Testament Fulfillment
If the Old Testament itself contains the seeds of the distinction between physical Israel and true, spiritual Israel, the New Testament brings this distinction to full flower. In the teaching of Jesus and the Apostles, it becomes clear that the true Israel of God is not defined by physical descent from Abraham but by faith in Jesus Christ.
Jesus and the True Israel
Jesus himself embodied the true Israel. He is the true Vine (John 15:1), replacing the nation of Israel which was repeatedly called God's vine in the Old Testament (Isaiah 5:1–7; Psalm 80:8–16). He is the true Son of God (Matthew 3:17), called out of Egypt as Israel was called out of Egypt (Matthew 2:15; cf. Hosea 11:1). He recapitulated Israel's history — passing through the waters of baptism as Israel passed through the Red Sea, spending 40 days in the wilderness as Israel spent 40 years, and where Israel failed He succeeded in perfect obedience.
The Church, united to Christ, is therefore the continuation and fulfillment of true Israel. As Christ is the true Israel in His own person, so those who are in Christ by faith share in His identity as the true Israel of God.
The Olive Tree of Romans 11
Paul's metaphor of the olive tree in Romans 11 is particularly illuminating. There is one olive tree — one covenant people of God. The natural branches (ethnic Israel) have been broken off through unbelief. Wild branches (Gentile believers) have been grafted in by faith. Ethnic Israelites who believe will be grafted back in to their own olive tree. The point is that there is one people of God, and membership in that people is determined by faith, not by ethnic identity.