Many Christians have no sense of history. They do not realize that the Bible not only contains progressive revelation but also contains a progressing history. Progressive revelation is where the Bible keeps expanding and amplifying its message throughout its contents. But the Bible also contains an historical progression from the nation of Israel to the church, the body of Christ. Paul was God's special agent in this progression. He wrote:
4 And by referring to this, when you read you can understand my insight into the mystery of Christ,
5 which in other generations was not made known to the sons of men, as it has now been revealed to His holy apostles and prophets in the Spirit;
6 to be specific, that the Gentiles are fellow heirs and fellow members of the body, and fellow partakers of the promise in Christ Jesus through the gospel—(3:4-6).
Christ told Paul brand-new information not found in the Gospels or the Old Testament. The information was that the Gentiles or non-Jews would be placed on absolutely the same footing as Jews who become Christians.