What does Acts 13:9 mean?

Saul is on the island of Cyprus (Acts 13:2–4) confronting a false Jewish prophet to protect a Roman proconsul (Acts 13:6–8) when his name in the narrative changes to Paul. He is no longer defined as a devout Jewish Pharisee (Philippians 3:5) and associate of the Sanhedrin (Acts 26:10). He identified himself as the one God has called to bring the gospel to the Gentiles.

There have been many speculations as to how Saul received the name Paul. Augustine suggested he rejected the name of the first king of Israel, a fellow Benjamite (1 Samuel 9:21), for a name that means small or humble (see 1 Corinthians 15:9). Jerome thought Saul followed the tradition of Roman generals who often took the name of the land they conquered in war. Since Saul "conquered" Sergius Paulus' paganism, he took Paulus' name. Another theory is that it was given to him by his family when he was young, maybe because he was little. Or perhaps his family received their Roman citizenship (Acts 22:28) when they were freed from slavery, as was common with those connected with the Roman family of Aemilian Pauli.

All these explanations are speculation. In that era, many Jews had both Hebrew and Greek names. The man directly opposing Paul, in this passage, is referred to as both Bar-Jesus (Acts 13:6) and as Elymas (Acts 13:8). Jesus took the Hebrew-named Simon and changed his name to the Aramaic Cephas (John 1:42), but he was most often referred to using the Greek Petros, or Peter in English. This is especially appropriate since Saul/Paul was born in Tarsus, outside Jewish territory. That Saul starts to go by the name Paul during his first significant ministry to Gentiles doesn't require a secret spiritual explanation.

Every Jesus-follower is indwelt by the Holy Spirit as a seal of our salvation and eventual glorification (Ephesians 1:13–14). The Holy Spirit started indwelling believers after Jesus ascended into heaven, on the day of Pentecost (Acts 2:1–4). Both Old Testament and church-age God-followers can be filled with the Holy Spirit, a usually temporary gift to accomplish God's work. Through Paul, the Holy Spirit confronts the false prophet and miraculously blinds him long enough to prove to the proconsul that Paul's message is true (Acts 13:10–12).