The Roman government had Paul as a prisoner, but he showed no bitterness and even used his position to help people.
After he survived a shipwreck and some people on an island rescued him and everyone from the ship, this happened, “And it happened that the father of Publius lay sick of a fever and dysentery. Paul went in to him and prayed, and he laid his hands on him and healed him. So when this was done, the rest of those on the island who had diseases also came and were healed” (Acts 28:8, 9).
Paul knew that as a Christian he would suffer unjustly, and such knowledge led him to continue to live as a Christian, which means to minister to others and not be bitter.