What made the pagan Gentiles come out of their immorality and become new creatures?
The gospel made the pagan Gentiles come out of their gross immorality and become new creatures in Christ. Paul defines that gospel as Christ dying for our sins according to the Scriptures, being buried, and rising again the third day according to the Scriptures. The gospel opens the door and transforms lives.
Les explains that Paul's priority was not baptism but preaching the gospel, lest the cross of Christ be made of no effect. Baptism had become a source of division, with people claiming baptism by Peter, Apollos, or Paul, and Paul thanked God he baptized none of them for that reason, though he recalled baptizing the house of Crispus and another. Water baptism was not the transforming power; the gospel had to open the door. It was the gospel that brought pagan Gentiles out of gross immorality and made them new creatures in Christ, and it transformed Jewish legalists into people of grace. Paul constantly refers to this gospel throughout his letters, defining it in chapter 15: Christ died for our sins according to the Scriptures, was buried, and rose again the third day according to the Scriptures. That is Paul's gospel and our gospel.