So he went in and out among them at Jerusalem, preaching boldly in the name of the Lord.
28. Luke saith afterwards that Paul went in and out with the disciples, which speech signifieth amongst the Hebrews familiarity, as the inhabitants of cities are said to go in and out at the gates of the city. Therefore after that Paul was commended by the testimony of Barnabas, he began to be counted one of the flock, that he might be thoroughly known to the Church.
Luke here makes no mention of Paul's journey into Arabia, which he tells us himself was immediately after his conversion, Gal 1:16, Gal 1:17. As soon as God had revealed his Son in him, that he might preach him, he went not up to Jerusalem, to receive instructions from the apostles (as any other convert would have done, that was designed for the ministry), but...
Commenting on Acts 9:23-31
And he spake boldly in the name of the Lord Jesus,.... He spoke the Gospel of Christ boldly, as it ought to be spoken; he spoke it openly, publicly, freely, and faithfully, not fearing the faces or revilings of any: the Vulgate Latin and Ethiopic versions add, "to the Gentiles"; but this is not in any of the Greek copies: and disputed against the Grecians...