For this reason, I, Paul, the prisoner of Christ Jesus on behalf of you Gentiles —Ephesians 3:1 HCSB

For what reason? The unity of the Body of Christ including the Gentiles.

At that time you were without the Messiah, excluded from the citizenship of Israel, and foreigners to the covenants of the promise, without hope and without God in the world.

Ephesians 2:12 HCSB

https://bible.com/bible/72/eph.2.12.HCSB

Why does Paul use "the prisoner of Christ Jesus on behalf of you Gentiles" as a title of himself? Would you put that on a business card? He at least addresses himself in this way in this letter. He is trying to make a point of himself and letting others know it as an example to follow. He is letting them know that he is in the chains of bondage in the physical to free those who are bound in the spiritual. To declare to the captive the freeing work of Jesus. He is saying that because He is bound in the chains of the Romans that those who are in Christ are free. 

“I wish before God,” replied Paul, “that whether easily or with difficulty, not only you but all who listen to me today might become as I am — except for these chains.”

Acts 26:29 HCSB

https://bible.com/bible/72/act.26.29.HCSB

The Spirit of the Lord is on Me, because He has anointed Me to preach good news to the poor. He has sent Me to proclaim freedom to the captives and recovery of sight to the blind, to set free the oppressed, to proclaim the year of the Lord’s favor.

Luke 4:18‭-‬19 HCSB

https://bible.com/bible/72/luk.4.18-19.HCSB

Christ has liberated us to be free. Stand firm then and don’t submit again to a yoke of slavery.

Galatians 5:1 HCSB

https://bible.com/bible/72/gal.5.1.HCSB

For you were called to be free, brothers; only don’t use this freedom as an opportunity for the flesh, but serve one another through love.

Galatians 5:13 HCSB

https://bible.com/bible/72/gal.5.13.HCSB

When was the last time we loved one another that we were willing to be arrested so that another could walk in the freedom of Christ? I am not saying go to jail to set someone else free. But rather give up some of your freedom to be tied up in time, finances, and home to help others hear the gospel or to be discipled in Jesus. When was the last time we gave up our car so that someone else may use it while they did not have one? When was the last time you opened your home to someone outside your family? When was the last time being a Christian cost you something? For Paul, it cost him a lot. For Jesus, it cost Him everything. For now, is the time it begins to cost us in the USA. Time to get off our cushioned pews and go out and be the church that Jesus came to die for!

Now the large group of those who believed were of one heart and mind, and no one said that any of his possessions was his own, but instead they held everything in common.  And the apostles were giving testimony with great power to the resurrection of the Lord Jesus, and great grace was on all of them.  For there was not a needy person among them, because all those who owned lands or houses sold them, brought the proceeds of the things that were sold,  and laid them at the apostles’ feet. This was then distributed for each person’s basic needs.

Acts 4:32‭-‬35 HCSB

https://bible.com/bible/72/act.4.32-35.HCSB