“Remember that Jesus Christ, of the seed of David, was raised from the dead according to my gospel, for which I suffer trouble as an evildoer, even to the point of chains; but the word of God is not chained.” – 2 Tim. 2:8-9
They thought they could shut Paul up by locking him up. Had he not been of God, perhaps that would have worked. However, Paul was of God; throwing him in a dungeon and throwing away the key did nothing to stop the Gospel. In fact, it had the opposite effect.
That’s because the word of God can never be chained.