Acts calls the apostle "Saul" in Jerusalem (Acts 7:58; 8:1, 3; 9:1), in/near Damascus (Acts 9:4, 8, 11, 17, 22, 24), in Tarsus (Acts 11:25), in Antioch (Acts 13:1,2) and in Paphos (Acts 13:7). While still in Paphos, the name "Paul" is introduced (Acts 13:9) and is used thereafter, including when leaving Paphos (Acts 13:13), in Pisidian Antioch (Acts 13:16), in Tyre (Acts 21:4); Caesarea (Acts 21:11, 13) and throughout his stay in Jerusalem, including in Jewish contexts (21:18 etc.). After Paphos (Acts 13:9) the name Saul appears again only at Acts 22:7, 13; 26:14 which refer back to the events of Acts 9 and quote the words of Jesus and Ananias.
It is normally assumed (without argument) that the switch of names occurs because Paul changed his focus to gentile audiences at this point. It is supposed that the name "Saul" was appropriate among Jews and the name "Paul" worked better among gentiles. This does not fit the data well. After all, he is called "Saul" as well as "Paul" in both Paphos and Jerusalem. Furthermore, he is called "Saul" in Antioch and Cyprus, which were gentile lands, and he is called "Paul" in the synagogue of Pisidian Antioch, for example.
Name recognition is very important for people in public life such as politicians and celebrities. A famous name can draw a crowd. A man who has become well known by one name may be understandably reluctant to change his name. It is common for high profile female professors and writers to keep their maiden names when they marry, instead of changing their names. Recently the famous author, JK Rowling wrote a book under a pseudonym and sold only 1500 copies until it was revealed that she was the author. Sales then increased by 150,000%! I have no reason to suppose that name recognition was any less important in the ancient world than it is in our time. Even those who have no particular fame are reluctant to change their names because of the confusion that it would cause. We need to ask whether the name "Saul" was important for the apostle. Was it useful to his career as a teacher and evangelist, or would he have been in a hurry to break with his past by abandoning the name at the earliest opportunity?
Saul, who had been a persecutor of the Jesus-believers, became a believer himself. This was a compelling narrative that was used not only by the author of Acts but by Paul himself (Phil 3:4-8). Indeed, from Gal 1:22-23 we gather that Saul's reputation was known by those who knew him only by name, not by face:
and I was still unknown by sight to the churches of Judea that are in christ; 23 they only heard it said, "The one who formerly was persecuting us is now proclaiming the faith he once tried to destroy."Saul's reputation no doubt have helped him gain an audience. It will also have allowed him to speak with authority against the zealous views the he had once held. The name "Saul" was useful to him wherever his reputation preceded him. Now, Saul's reputation was known in Jerusalem (Acts 9:26-27), and some of those whom Saul had persecuted preceded him to Cyprus and Antioch:
Acts 11:19 Now those who were scattered because of the persecution that took place over Stephen traveled as far as Phoenicia, Cyprus, and Antioch.In Antioch and Cyprus, as in Jerusalem, Saul was already known by name, at least by believers. How did he interact with those whom he had previously persecuted? Judging from 1 Cor 15:9, for example, he would have taken full responsibility for his actions:
For I am the least of the apostles, unfit to be called an apostle, because I persecuted the church of God.It seems that he retained the name "Saul" in those regions instead of taking an alias to disguise the fact that he was Saul, the persecutor of the church.
Tarsus in Cilicia was Saul's place of birth and presumably he had friends or relatives there. We don't know what name he was called there.
When Paul left Paphos he sailed for Perga in Pamphilia and from there he went to south Galatia. His intention may have been to go even further, since it was only because of an illness that he went to Galatia (Gal 4:13). In any case, his journey took him through territories that were further from Jerusalem and had no existing Christians, as far as we know. When Saul was in Paphos he was contemplating a journey to places where few, if any, people knew his name. It was therefore the ideal time for Saul to take a new name. The name "Paul" worked well. It's phonetic similarity with the name "Saul" helped to avoid confusion: it was easy for people who had heard of "Saul" to realize and remember that he had changed his name to "Paul". I argued in an earlier post that he took the name "Paul" because of its meaning (small) and that the name may have come to Saul's mind because of Sergius Paulus.
To sum up, the timing of the switch of names in Acts adds no support the view that Saul adopted the name "Paul" merely because it was more familiar to gentiles. The fact that he did not become "Paul" immediately after his conversion is no argument against the view that he chose the name to reflect his new Christian identity. He retained the name "Saul" because that was the name by which he was already known and he switched to "Paul" in preparation for a journey to places where he had little invested in his earlier name. He kept the name "Saul" for so long for the simple practical reason that people knew him by that name. I learned this from John Chrysostom who writes
But why did [the Holy Spirit] not change the name immediately, but rather allowed much time to pass? Because, if [the Holy Spirit] had changed his name immediately, then Paul's change, and his turn toward the faith, would not have become known... If, immediately upon leaving the Jews, he had come to us after changing his name, no one would have known that the persecutor himself was the evangelist. This was the amazing thing, that the persecutor had become the apostle. hom. 3 in Ac. 9:1 (PG 51:137; edited) quoted by Michael Compton in From Saul to Paul: Patristic Interpretation of the Names of the Apostle in In Dominico eloquio 66-67.Ignore Chrysostom at your peril.