In Acts 9 we read about the conversion of Saul. Saul was a mean dude intent on uprooting the church. He probably thought he had God on his side while he was blessing the murder of Stephen (7:58, 8:1). But here we read of the radical power of the gospel to forgive sin.
Saul is converted, but few trust him. (would you?) Yet this man who has been intent on persecution now stands up and testifies to the power of Jesus Christ to change lives. How amazing is God that he would take perhaps the strongest voice against Christianity and use him instead to promote the gospel message.