Ephesians 3:6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:

Paul is revealing a mystery here; he is revealing that the Gentiles are to be joint heirs with Christ. Gentiles are not fellowheirs with Israel; Israel is fallen temorarily. Israel is set aside as a nation, and now, Jews may become heirs of Christ freely by the propitiation of Christ, by believing the gospel of Grace. Romans 8:17 Galatians 4:7 Romans 11:12 Romans 3:24 Romans 1:16

Both Jew and Gentile, through faith in the gospel of Christ, are of the same body, the body of Christ, and have become, members one of another, a new creature. Galatians 3:28 Romans 12:5 Galatians 6:15

Revealed is that the Gentiles, by the gospel, are partakers of his promise in Christ. Galatians 3:29