Here are some interesting tid-bits of information that gave me some new insight into Paul’s history and motivation. Fun stuff!
Was Paul His Real Name?
originally posted at Jewish Studies for Christians
It is a common thing for modern Christ-followers, who are keenly aware of the Jewish Background of New Testament Scriptures, to struggle with how “the beloved apostle” should be referred to.
Do we refer to him as Rav Shaul (Rabbi Saul) as many today do? Do we keep on calling him with the non-Jewish sounding phrase Apostle, or perhaps even, St. Paul? Do we do something far less practical, but probably more true to history and refer to him as Saul/Paul? Please, let me assure you that these and other questions you are asking are perfectly legitimate.
Nobody knows how he got his Latin name Paul (the name is actually not Greek). Given the fact that he was born a Roman citizen (Acts 22:28) it is likely that both Jewish and Roman names were given to him at birth by his parents. The Greek versions of both Saul (Σαá¿¦λος) and Paul (Παá¿¦λος) are remarkably similar. In fact, there are different by only one beginning letter. This practice of matching names was wide-spread.  Whether the names were or were not matched, it is clear that Jews had double names like that often. Another well-known example of such a double name would be John Mark. John or Yohanan – a Hebrew/Jewish name and Mark or Markus a Latin one (Acts 12:12, 25; 15:37).
It is interesting that Luke (and Luke’s Jesus) uses his Hebrew name Saul first, but at some point later (Acts 13:9), and that unconnected to his Road to Damascus experience that happens way earlier (Acts 9:4), begins to call him Paul.
What may be significant is that Saul was the first king of Israel, and in spite of his eventual fall, was characterized by a large and strong body, continuing in some way to inspire Jewish devotion in naming children. Not only King Saul was from the tribe of Benjamin [like Saul/Paul], but so was the legendary Jewish sage Rabbi Hillel who lived before Jesus.
Incidentally, Paul makes a reference to his affiliation with this particular tribe as one of his reasons for his human confidence (Phil.3:5). In opposition to that, “Paul” in Latin, means “small” or “little”. So, the switch (if there was ever one indeed) is better explained not by Paul’s so-called “conversion from Judaism to Christianity”, but by his own realization, and perhaps accompanied by his direct request to Luke, of his own standing before his God. In fact as his life progressed, so progressed this realization of his own sense of smallness and weakness before the grandeur and power of his no longer tribal deity (1 Cor.15:9; Eph.3:8; 2 Cor.12:9).
 While this insight is not original to him I am truly indebted to my colleague Prof. Peter Shirokov in pointing me in the right direction.