4 As you read what I have written, you will understand my insight into this plan regarding Christ. 5 God did not reveal it to previous generations, but now by his Spirit he has revealed it to his holy apostles and prophets. 6 And this is God's plan: Both Gentiles and Jews who believe the Good News share equally in the riches inherited by God's children. Both are part of the same body, and both enjoy the promise of blessings because they belong to Christ Jesus.
Matthew Henry's Commentary on Ephesians 3:4-6
Commentary on Ephesians 3:1-7
(Read Ephesians 3:1-7)
For having preached the doctrine of truth, the apostle was a prisoner, but a prisoner of Jesus Christ; the object of special protection and care, while thus suffering for him. All the gracious offers of the gospel, and the joyful tidings it contains, come from the rich grace of God; it is the great means by which the Spirit works grace in the souls of men. The mystery, is that secret, hidden purpose of salvation through Christ. This was not so fully and clearly shown in the ages before Christ, as unto the prophets of the New Testament. This was the great truth made known to the apostle, that God would call the Gentiles to salvation by faith in Christ. An effectual working of Divine power attends the gifts of Divine grace. As God appointed Paul to the office, so he qualified him for it.