What does Ephesians 6:20 mean?

Paul viewed himself not merely as a lowly prisoner, but as "an ambassador in chains." He was a representative of the King of kings, albeit one in captivity. As a prisoner under house arrest, Paul might have still been literally chained in his apartment. In some cases, prisoners were shackled to a Roman solder, which may have stirred Paul's analogy of the armor of God. Others view the reference to chains as a generic metaphor for his imprisonment. Regardless, Paul had already spent previous time in literal chains for the faith and could rightly use this title.

Further, Paul noted that declaring God's truth boldly was the right thing to do. He did not view being quiet about his faith as honorable. Instead, he asked for faith to speak even more boldly about Christ. This was quite admirable, given the fact that he was already imprisoned because of his preaching of the gospel. Paul refused to back down, and rather wanted to become even bolder in presenting the good news of Jesus Christ.