Jamieson, Fausset and Brown on Acts 9:27

27. But Barnabas ... brought him to the apostles--that is, to Peter and James; for "other of the apostles saw I none," says he fourteen years after (Ga 1:18, 19). Probably none of the other apostles were there at the time (Ac 4:36). Barnabas being of Cyprus, which was within a few hours' sail of Cilicia, and annexed to it as a Roman province, and Saul and he being Hellenistic Jews and eminent in their respective localities, they may very well have been acquainted with each other before this [Howson]. What is here said of Barnabas is in fine consistency with the "goodness" ascribed to him (Ac 11:24), and with the name "son of consolation," given him by the apostles (Ac 4:36); and after Peter and James were satisfied, the disciples generally would at once receive him.

how he had seen the Lord ... and he--the Lord.

had spoken to him--that is, how he had received his commission direct from the Lord Himself.