Acts 9:28

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…

And he was with them ... - That is, he was admitted to their friendship, and recognized as a Christian and an apostle. The time during which he then remained at Jerusalem was, however, only fifteen…

He was with them coming in and going out - Freely conversing and associating with them; but this seems to have continued only fifteen days. See Gal 1:18.

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…

And he was with them, &c. i.e. for the fifteen days during which his visit lasted he was received into the fellowship of the Church.