One of the most common misconceptions in the New Testament is that Saul, persecutor of the early Christian Church, changed his name to Paul after converting to Christianity.
Many even believe that God changed Saul's name to Paul.
However, when we read the New Testament we find that God never changes Saul's name to Paul. When God speaks to Saul, he uses his Hebrew name.
And he fell to the ground and heard a voice saying to him, “Saul, Saul, why do you persecute me?” And he said, “Who are you, Lord?” And he said, “I am Jesus, whom you are persecuting
The first time we see Saul referenced as Paul is much later in the Acts of the Apostles.
But Saul, who is also called Paul, filled with the Holy Spirit, looked intently at him.
Most biblical scholars point out that Saul had two names, one Hebrew and the other Latin, as the Catholic Encyclopedia explains.
As he belonged to the tribe of Benjamin he was given at the time of his circumcision the name of Saul, which must have been common in that tribe in memory of the first king of the Jews (Philippians 3:5). As a Roman citizen he also bore the Latin name of Paul. It was quite usual for the Jews of that time to have two names, one Hebrew, the other Latin or Greek, between which there was often a certain assonance and which were joined together exactly in the manner made use of by St. Luke (Acts 13:9: Saulos ho kai Paulos).
If Saul had two names, why does the rest of the New Testament use his Latin name?
Many believe this switch by St. Luke in the Acts of the Apostles represents his new mission to the Gentiles, who spoke Latin/Greek.
It was natural that in inaugurating his apostolate among the Gentiles Paul should have adopted his Roman name, especially as the name Saul had a ludicrous meaning in Greek.
Simply put, God did not change Saul's name. Saul wanted to reach the Gentiles and needed to use his Roman name in his many travels.
