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Not only does the bible not teach that there are two distinct peoples of God, Israel and the Church, but it is very explicitly opposed to this idea. For one thing, the Church existed in the Old Testament, long before the outpouring of the Spirit on the Day of Pentecost
(see Acts 7:38); and furthermore, the clear teaching of the New Testament is that the modern day Church is really just the expansion of God's people Israel. According to Paul, being an Israelite has never been based merely on outward ethnicity
(Rom. 2:28-29; 9:6-8); but those who have been called according to God's promise are Abraham's true seed
(Rom. 9:8). Hence, all who have faith are Abraham's children, and the true Israel of God
(Rom. 4:11-17; Galatians 3:6-9, 26-29; 4:21-31; 6:16; Phil. 3:3; 1 Pet. 2:9-10; Rev. 2:9).
When Paul deals extensively with the whole question of the place of Jews and Gentiles in the people of God, in
Romans 11, he shows that there is just one people, symbolized by one good olive tree; unbelieving ethnic Jews may be broken off of that tree of true Israel and believing Gentiles may be grafted in; but there is still one tree, one body, one people of God. Thus, Paul teaches elsewhere that there is no difference between Jew and Gentile in Christ
(Gal. 3:26-29; Col. 3:11), but that all believers are members of the same body, citizens of the one commonwealth of Israel, inheritors of all the promises made to Abraham
(Eph. 2:11-22; 3:6; Gal. 4:26-31; Phil. 3:20; Heb. 12:22-23). In short, there is and always has been one people of God, and that people includes all those who are grafted in to God's “good olive tree” to become Abraham's children by faith, whether ethnic Jews or Gentiles.
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