1For this reason I, Paul, a prisoner for Christ Jesus on behalf of you Gentiles— 2assuming that you have heard of the stewardship of God’s grace that was given to me for you, 3 how the mystery was made known to me by revelation, as I have written briefly. 4 When you read this, you can perceive my insight into the mystery of Christ, 5which was not made known to the sons of men in other generations as it has now been revealed to his holy apostles and prophets by the Spirit. 6This mystery is that the Gentiles are fellow heirs, members of the same body, and partakers of the promise in Christ Jesus through the gospel.
Why is Paul a prisoner for the Gentiles? Because of the Gospel of God's grace! It is not just enough to know of God's grace, one must experience it to receive the full benefit. Paul was given a huge experience of God's grace. One who was once a murderous opponent now a zealous apostle. Why? Not for Paul's sake, but it was "given to me for you." In other words, it was given to Paul that God's grace might be known to the Gentiles.
Paul speaks of the mystery of Christ, which was not made known to other generations. Not a mystical knowledge, but the mystery of how God's love would work itself out on a cross. No one, even the most learned Jewish scholar at that time saw that one coming. And even in his current generation, it is revealed to his apostles and prophets. But not for their sake. Grace is never given for the sake of the one receiving it, it is given that God's grace might be known to others.
So what about the grace God gives you and me? If God did not give it to us for our own sake, and He did not, what are we doing to share it with others that they might see it. This light was not meant to be hidden under a basket.