Philippians 1:3-8

Saul was on his way to destroy more Christians when Jesus stepped in and changed his life forever. He was transformed from someone who violently hated Jesus and his followers to one who loved Jesus and the members of His church. He wants people to understand the source of this transformation lies in the love of Christ within him. 

The Holy Spirit shows us through Paul's life what it is like to have your life changed through Christ (gain love, gratitude, joy). Those who are grateful are ready to worship God. You can't have joy without an attitude of thanksgiving.