Paul or Saul
The apostle Paul was called Saul when we are introduced to him. Then at some point he is referred to as Paul, and he is called that in all the ensuing writings. What is going on here?
The popular conception is to see this as a parallel case to Abram and Jacob, who had a significant experience with God, and then God gave them a new name, reflecting their new identity (Gen. 17:5; 32:28). Many of us have an image that at some point God said, "You will no longer be called Saul, but you are now Paul, for you are a Christian." Unfortunately, this image does not match the reality that the scriptural data presents.
The name "Saul" is the Hebrew name "Sha-ul", the name of the first king of Israel. This is his name at the time of his vision, and it continues to be his name during his year-long ministry at Antioch. If we consider the chronology in Galatians, there were another three years between his vision and his going to Jerusalem at the end of Acts 11. When and under what circumstances is he referred to as Paul?
In chapter 13, after at least four years of being called Saul among the believers, he is singled out by the Holy Spirit, who says, "Set apart for me Barnabas and Saul for the work to which I have called them". So Barnabas and Saul, two elders of the congregation in Antioch, set out and travel to Cyprus. It is during the account of their ministry there that we encounter this verse (13:9): "Then Saul, who was also called Paul,..." The impression is that he went by either name, depending on the circumstances. In the rest of the account in Acts and in his epistles he is referred to by his Greek name, "Paulos".
As a matter of fact, it was common then, as it is now, for Jews to have a Hebrew name that they used in Jewish contexts, and a "Gentile" name that fit the culture in which they lived. Peter is a good example of this. He had a Hebrew name, Simon (Shim-on), an Aramaic name, Cephas, and a Greek name, "Petros". He was called by all three, depending on the setting. Another example is in Acts 1:23. Joseph (Hebrew) is called Bar-sabbas (Aramaic) and Justus (Greek).
Acts, as you know, was written to a Gentile, Theophilus, somewhere in the Diaspora. Therefore, there is a preference for Greek names. When Saul goes from a Jewish setting, his congregation in Antioch, to Cyprus and beyond, he is referred to by his Greek name. When he writes to Gentile congregations, he similarly identifies himself by his Greek name.
The point is this. In the understanding of many people there was a significant change in the identity and outlook of this man that was symbolized by a name change, from Saul to Paul. In the New Testament account, however, he changed from Saul, the Jewish Pharisee who resisted Jesus and the Way (a Jewish sect) to Saul the Jewish Pharisee who embraced Jesus and the Way, and was commissioned to tell the Gentiles. This was definitely a change in attitude and purpose, but not a change in identity or core beliefs, except regarding Jesus.
Paul and the Synagogue