Acts 9:27

But Barnabas took him, and brought him to the apostles i.e. to such of the Apostles as happened to be then in Jerusalem. During a short space of fifteen days it is easy to understand that all but Peter and James might be absent from Jerusalem. St Paul tells us he only saw these two during his visit (Galatians 1:19), and all that he says is perfectly consistent with St Luke's narrative. Barnabas, who introduced Saul to the Apostles, has already been mentioned as a Levite of Cyprus (Acts 4:36), and from the proximity of Cyprus to Cilicia, and the distinction of the schools of Tarsus, a conjecture has been hazarded that Barnabas may have been known to Saul before they came to Jerusalem. This would explain how it came to pass that while the other disciples were afraid of him, Barnabas listened to his statement and repeated it to the rest of the Church.

and declared unto them how he had seen the Lord in the way, &c. It is worthy of notice in how many forms the statement of the appearance of Jesus to Saul is repeated. This was indeed the turning-point of the Apostle's life, Jesus of Nazareth seen as the glorified Son of God.

and how he had preached[spoken] boldly at Damascus in the name of Jesus Whether the knowledge of Barnabas was derived from Saul himself or from other sources we are not told, but in the political turmoil of the times (see Acts 9:24, note) we may easily suppose that the teachings of a preacher who appeared for a brief space, and then retired from Damascus, and who had only lately reappeared, would not be widely known among the Church at Jerusalem.