Ephesians 3:1-5

For this reason [because I preach that you and believing Jews are joint heirs] I, Paul, am the prisoner of Christ Jesus on behalf of you Gentiles— assuming that you have heard of the stewardship of God’s grace that was entrusted to me [to share with you] for your benefit; and that by [divine] revelation the mystery was made known to me, as I have already written in brief. [Eph 1:9] By referring to this, when you read it you can understand my insight into the mystery of Christ, which in other generations was not disclosed to mankind, as it has now been revealed to His holy apostles and prophets by the [Holy] Spirit