Matthew Poole and continuators on Acts 13:9

9 Then Saul (who also is called Paul) filled with the holy Ghost, set his eyes on him▪

It is observable, that St. Luke never before called this great Apostle by the name of Paul: and henceforth never calls him by the name of Saul; tho there be no great difference in these names. Saul might be more acceptable to the Iews ▪ amongst whom hitherto he had conversed. And Paul a more pleasing name unto the Gentiles, unto whom he was now sent, and with whom for the future he should most converse. He was called Saul as he was a Iew born, an Hebrew of the Hebrews; and Paul, as he was a Denison of Rome. The Romans having that name in good account in several of their chief Families.

Zeal for Gods Glory, and Faith and Power to work the ensuing Miracle.