Paul, an apostle of Christ Jesus by the will of God,
To the saints who are in Ephesus, and are faithful in Christ Jesus: (ESV)
Perhaps you have heard the expression, "Where there is a will there is a way." This has some general truth to it. I think we can agree that those who have found a way to do great things were also people who had a strong will to do so. They were people committed to a task. Perhaps you have a strong-willed child and they drive you nuts. That child may grow up to do great things, provided their will is attached to a good purpose.
Paul was a strong-willed man. By his own efforts he had pursued Judaism to its highest levels. When this upstart "Christian" faith showed up he not only disagreed with it, he was having Christians put to death for their faith. Paul describes his strong willed behavior in Philippians 3:4-7:
 though I myself have reason for confidence in the flesh also. If anyone else thinks he has reason for confidence in the flesh, I have more:  circumcised on the eighth day, of the people of Israel, of the tribe of Benjamin, a Hebrew of Hebrews; as to the law, a Pharisee;  as to zeal, a persecutor of the church; as to righteousness under the law, blameless.  But whatever gain I had, I counted as loss for the sake of Christ. (ESV)
His will achieved for him status among his Jewish brethren. His will achieved for him bragging rights among men. But God's will achieved for him something far greater. In fact, Paul says "whatever gain I had, I counted as loss for the sake of Christ." By God's will, Paul was called unto salvation. By God's will Paul was given eternal life. By God's will Paul was an Apostle.
Are you strong-willed? Are you trying to make something of yourself? Are you looking for bragging rights when being compared to your neighbor? I challenge you to surrender your will to God. He calls you to salvation. He calls you to a new life in Him. Whatever gain you might think you have achieved in life by your own efforts, consider it loss for the sake of Christ. Fill in this sentence: I am______________________, by the will of God.