I know how to be brought low, and I know how to abound. In any and every circumstance, I have learned the secret of facing plenty and hunger, abundance and need. (Philippians 4:12 NKJV)
Paul was able to find joy and contentment in the midst of terrible situations. All of these were the direct result of his boldness for the gospel. How did he do that?
Paul cared less about what God's will was than he did about being faithful in it. When he knew he was in the will of God, the difficulties of his circumstances paled in comparison to knowing that He was being obedient to God.
True contentment is knowing what God's will is and living by faith in it.
"Live to the hilt in every situation you believe to be the will of God."
- Jim Elliott