Ephesians 3:6 This mystery is that the Gentiles are fellow heirs, members of the same body, and partakers of the promise in Christ Jesus through the gospel.
The mystery of the inclusion of Gentiles was not revealed to the Old Testament prophets. The fact that Gentiles would be partakers of the promise through a new entity [The church] was not fully revealed to them. Nothing could be more inaccurate than to think of the nation of Israel as the Old Testament church, since they were not a spiritually redeemed people except for a small remnant. Israel was and is a physical nation of one people group, whereas the church is a spiritual body of all ethnic groups. Paul makes it clear in Ephesians 2:11-22 that the church began with the new covenant and the new man in Christ, which precludes any possibility that the church existed in the Old Testament era.
Focus on Christ #48