As the comments below highlighted to me, it is possible that Paul didn’t change his name. Rather, as it says in Acts 13:9, Saul ‘was also called Paul’ — i.e. he (always had) had two names. Referring to the Saul/Paul, F. F. Bruce says:
He was born into an orthodox Jewish family, and as his father was a Roman citizen, he inherited this distinction, a rare one among eastern Jews. In Jewish circles he bore the name of Saul, but in the Gentile world he was commonly known by his Roman cognomen Paullus, Anglicized as Paul […]
Saul’s father was a Roman citizen… [so] Saul was born a Roman citizen… As a Roman citizen, he had a Roman name, consisting of three parts: praenomen, nomen gentile and cognomen.2 What his praenomen (first or personal name) and nomen gentile (family name) were we can only guess; his cognomen, however, was Paullus, by which (in its English form Paul) we usually call him.
In family circles, however, he was known by his Jewish name Saul.
2. The threefold Roman name may be illustrated from the full names of such famous Romans as Gaius Julius caesar, Marcus Tullius Cicero, Lucius Cornelius Scipio. …
— F. F. Bruce, The Spreading Flame (Exeter: Paternoster Press, 1958), p. 18, 81
However, even if Saul/Paul didn’t change his name, after Acts 13:9 the Biblical record, as one commenter points out below, definitely shifts from referring to him as Saul and, instead, refers to him as Paul. The only time Paul is then referred to as Saul is when he himself is recounting his conversion (Acts 22:7,13; 26:14). We could legitimately ask why this shift happens.
Although we aren’t told why there was a shift, here is a possibility:
Saul was also the name of the first human king of Israel (God was the first king: 1Sam. 8:7); that Saul was very tall (1Sam. 9:2) and he also became a very bad king (1Sam. 15). King Saul was a good king when he was ‘small in his own eyes’ (1Sam. 15:17) — i.e. when he was a humble person. When he became proud he became a wicked king.
In contrast, Paul means little or small — perhaps Paul himself instigated the shift from being referred to as Saul to being referred to as Paul because once he had been a bad person, proud (Phil. 3:4-6), like king Saul, but now he was a Christian trying to be humble (Phil. 3:7-11). Perhaps he saw ‘Paul’ now as the more fitting of his names.
Another possibility (as suggested in a comment below) is that Paul chose ‘Paul’ over ‘Saul’ because he was, by and large, a preacher to gentiles (i.e. non-Jews; Rom. 11:13), so his gentile name would possibly be more preferable in such circumstances.
It’s possible that he always had two names — Saul being his Jewish name and Paul his Roman name. This was quite common, especially for someone who was both Jewish and a Roman citizen. His apparent change of preference to use Paul rather than Saul may also have been to help in his efforts to preach to non-Jews.
David Rohl proposes that Saul himself had a name change, that his original name was “Lebayu” (though everything proposed by Rohl is controversial)
In Acts 13:9, we read “Saul who was also called Paul.” So, it wasn’t a name change, he was also known as Paul. See, Paul was a Roman citizen, and Romans had 3 names; the first was known as “Pranomen” which was just a title formality. the second name was known as “nomen” and it identified the tribe you came from or identified the person from whom you received Roman citizenship. The third name was the most important, it was known as your “cognomen” which identified your family name. Saul was Paul’s Hebrew name, and many scholars believe that he was named after king saul because they were both from the tribe of Benjamin, Saul’s Latin name, “Paul” is actually his cognomen “Paulus” and it means “small” and many scholars believed that he took up that name because according to 1 Corinthians 15:9, he wanted to be known as the “least” of all the apostles, or the smallest, which would signify his cognomen “Paulus” meaning small.
is there any other scripture to confirm that paul’s name was change
All we know is that every reference before Acts 13:9 talks about Saul, and the only references to Saul after that are when Paul is telling people about what happened before that time. Everywhere else he is referred to as Paul. And it isn’t just that Acts has changed from referring to Saul to referring to Paul, because all his letters use the name Paul as well. This clean break seems like it could suggest a permanent change in name, though it could just be a result of the name making his mission to the Gentiles more approachable, as suggested in the first comment.
So no, there doesn’t seem to be any other scripture that confirms that his name was changed, but the name used in the record definitely changed at that point.
did saul change his name to paul to start new so he could try forget about what he use to do?
It’s possible. We don’t have any further information on why he changed his name, so anything else is just a guess.
St Paul is the foremost apostle to the Gentiles. To become this Jesus radically changed him.
With regard to to his name change I suggest the following:-
Before his conversion Saul, (a Jewish name and associating him with the tribe of Benjamin), persecuted the Christians and he was well known. On conversion he realised by revelation that Jesus teaching was for all people. In order to set out on his mission for Jesus specifically to the Gentiles, a change of name would help him as the ‘new man’ that he had become according to the intellectual miracle that he received from Jesus.
It is a myth (probably born of anti-Semitism) that God changed his name to Paul at his conversion. If God had changed his name, why would the Holy Spirit call him “Saul” some 14 years after his conversion (Acts 13:2)? If he (or God) changed his name to indicate his ministry was to the Gentiles, why when he is in Paphos? God says this is his part of ministry just after his conversion (Acts 9:15) and Paul understands this is his calling well before he leaves Antioch, before the Holy Spirit calls him “Saul”.
The simplest explanation is that “Saul who was also Paul” (literal Acts 13:9) is because of Sergius Paulus the proconsul. Something happened at the court when he was shown to be approved by God in the blinding of Elymas that changed the dynamics of the mission. Barnabas is no longer the precedent (‘Barnabas…Saul’ becomes ‘Paul… Barnabas’) and Saul is never called Saul again.
I suggest that the simplest explanation is that Sergius Paulus becomes benefactor of Paul or adopts Paul, probably informally, and Paul takes his name. This may be why Paul speaks so eloquently of God’s adoption of us as sons. Roman ‘adoption’ conferred legal protection and rights similar to those Paul speaks of when he talks about how God has ‘adopted’ us into His family through His Son, Jesus Christ. It is a uniquely Roman, and not a Jewish, perspective.
saul, a roman – persecuted Jesus’ followers even condoning the stoning of Stephen. Jesus appeared to saul and asked him – ‘why are you persecuting me? acts chapter 9
saul converted to Christianity and became the apostle paul
In writing the Gospels and other letters, it was natural for the Apostles to transliterate their own names. They were living in a multilingual world…
I think Luke chooses to use Paul’s other name after his conversion to allude to the complete rebirth that had occurred. Maybe also to draw comparison to Peter’s name change given by Christ. The two (Peter and Paul) were similar since one was sent to the Greeks and the other to the Jews.