One sentence determined his theology: I am Jesus, whom you are persecuting (Acts 9:5b). Jesus was mysteriously identified with peoplethe loving group of people Saul had been running down like criminals. Jesus, he saw, was the mysterious fulfillment of all he had been blindly pursuing.
From then on, his only work was to present everyone perfect in Christ. For this I labor and struggle, in accord with the exercise of his power working within me (Colossians 1:28b-29). For our gospel did not come to you in word alone, but also in power and in the Holy Spirit and [with] much conviction (1 Thessalonians 1:5a).
Pauls life became a tireless proclaiming and living out of the message of the cross: Christians die baptismally to sin and are buried with Christ; they are dead to all that is sinful and unredeemed in the world. They are made into a new creation, already sharing Christs victory and someday to rise from the dead like him. Through this risen Christ the Father pours out the Spirit on them, making them completely new.
So Pauls great message to the world was: You are saved entirely by God, not by anything you can do. Saving faith is the gift of total, free, personal and loving commitment to Christ, a commitment that then bears fruit in more works than the Law could ever contemplate.