Paul's missionary journey led to the development of Christianity as a world religion. It was not a Jewish sect but open to everyone: Jews and Gentiles, all of whom were drawn to Jesus of Nazareth's countercultural teachings of love, forgiveness and salvation for all believers. Jewish Christians believed that gentiles first had to convert to Judaism and follow the laws of Moses including circumcision and the dietary laws of kashrut. Paul challenged this belief in the council of Jerusalem in 50ce. His contributions at this Council of Jerusalem enabled gentiles as well as Jews to be followers of Jesus of Nazareth and call themselves "Christians ". This significantly altered the course of history because it led to the rapid and amazing expansion of Christianity through the salvation of new believers. In this way, Paul made Christianity accessible to all, whether they were "Jew or Gentile, male or female, freed or slave " Galatians 3:28.This revolutionized religious expression as salvation was previously earned through works (sacrifices and commandments). .
Paul, building on Jesus teachings, taught that salvation could be reached not by just obeying commandments, but rather "to all who believed in God alone. " Romans 2:4-5. This belief was predominately lost until it was taken up by Martin Luther in the Protestant reformation. Therefore, Christianity expanded and was transformed by this and its nature and expression significantly developed as a result. Paul also reiterated the importance of relying on Jesus, which is expressed in his letter to the Colossian church. Their reliance on the self was causing nothing but trouble for their spiritual lives, and Paul was quick to point this out. Rather than testing human capabilities, Paul promoted the idea of keeping faith in the works of God, through constant prayer and reading of God's word. Paul believed this would lead to a spiritually stronger church.