"Of this church I was made a minister according to the stewardship from God bestowed on me for your benefit, that I might fully carry out the preaching of the Word of God, that is, the mystery which has been hidden from the past ages and generations; but has now been manifested to His saints, to whom God willed to make known what is the riches of the glory of this mystery among the Gentiles, which is Christ in you, the hope of glory," (Colossians 1:25--27).
* The divinely-ordained ministry Paul fulfilled was in preaching the mystery of Christ. The church was hidden from the Old Testament prophets, but was revealed at Pentecost, and through Paul's ministry. The Lord Jesus taking residence through the Person of the blessed Holy Spirit in both believing Jews and Gentiles is, indeed, a tribute to God's amazing wisdom.
* As the apostle to the Gentiles, Paul revealed an amazing truth--- a mystery--- that Christ's body, the church, (consisting of all the elect, past, present, and future), would be composed of both redeemed Jews and Gentiles. Such an entity was not revealed to the Old Testament prophets. That Christ would be in us who believe, both Jew and Gentile, is surely the hope of glory!