The New Testament church differs significantly from its Old Testament counterpart. The New Testament church is made up of both Jews who have accepted Jesus as Messiah and Gentiles who also believe in Jesus Christ. JTL23 7.1
Paul illustrates the new organic relationship of these diverse peoples by the imagery of two trees—a good and a wild olive tree, representing Israel and Gentiles. The Jews who do not accept Christ are no longer the children of God (Romans 9:6-8) and are represented by branches broken off from the good tree, while those Jews who did receive Christ remain attached. Paul goes on to portray the Gentiles who accept Christ as branches from the wild olive tree grafted into the good tree (Romans 11:19-25). Thus, the apostolic church became an independent organization with no national boundaries, the church of Christ universal. JTL23 7.2
All the covenant blessings God made to ancient Israel were predicated on Israel’s wholehearted obedience and cooperation with God’s will. When God’s own people “received Him not” (John 1:11), spiritual Israel—those who have received Christ as Savior—became the recipients of the covenantal promises. Individual Jews could still be part of spiritual Israel, but they would do so as believers in Christ as Messiah (Romans 9:6; 1, 2). JTL23 7.3