Barnabas and Saul, being sent out by the Holy Spirit, end up in Cyprus via Seleucia (cf. 4.36). They travel the whole country from East to West proclaiming the word of God in the synagogues of the Jews. It seems they had help on this trip from the writer of the Gospel of Mark (cf.12.25).
Arriving to the west coast town of Paphos – a place as beautiful now as it was then – they encounter a false prophet named Bar-Jesus. We read that he was with the proconsul, a Roman-installed ruler. Interestingly, there is extra-Biblical evidence in Cyprus that this man, Sergius Paulus, was there at this time and that he did come to faith in Christ (v.12) ¹.
The false prophet – Elymas the magician – does all he can to prevent the Gospel from being declared (v.8) and we then read that Saul, who was also called Paul, said this:
“You who are full of all deceit and all wrongdoing, you son of the devil, you enemy of all righteousness—will you not stop making crooked the straight paths of the Lord? Now look, the hand of the Lord is against you, and you will be blind, unable to see the sun for a time!”
(Acts 13.10-11, NET)
The false prophet is then blinded (v.11b) and as a result of the miracle the proconsul believed. Seeing the power of the Gospel in action led a man to faith. Being astonished at the teaching of the Lord and seeing it in action led Sergius Paulus to faith.
Again, if we are thinking of Acts as being prescriptive or descriptive, does this passage mean we are to go around pronouncing temporary blindness on those who oppose the Gospel? Or, rather, does it show that the best way to win people to faith is to demonstrate the power of the risen Lord Jesus in your life? Sergius Paulus saw the Gospel in action, its ability to silence and confound its own critics. He saw the courage of those who are submitted and committed to it and he saw the results of an encounter with the Word of God in those who oppose it. He saw these things and he believed.
¹ – https://biblearchaeologyreport.com/2019/11/15/sergius-paulus-an-archaeological-biography/