Luke divides Saul’s visit to Damascus into a few days in Acts 9:19 and into “many days” of preaching and debating with those having an opposing point of view concerning Jesus in Acts 9:20-23. Luke doesn’t mention Saul’s time in Arabia, but Saul claims he spent over two years there (Galatians 1:18), before returning to Jerusalem three years after he originally left for Damascus and this two-plus-year period comes between verses 19 and 20 in Acts 9.
Did Saul preach at all during his first visit to Damascus, immediately following his conversion? If he did, it could not have been more than offering his testimony and witnessing about his vision of the resurrected Jesus on his way to the city. Nevertheless, Acts 9:21 seems to preclude any preaching until his return visit from Arabia. The Jews at Damascus seem to be completely surprised about Saul’s conversion. One wouldn’t think they would have been had he preached in any of the synagogues in the city on his first visit. Moreover, the ignorance of Jerusalem three years later concerning Saul’s status also seems to indicate that except for a few believers with whom Saul met after his baptism, no one was aware of his conversion!
One can only guess what those first few days were like for Saul as Ananias came into Judas’ guesthouse on Straight Street where Saul waited for him. Who was Ananias? No one really knows. He is one of those obscure, but important figures in God’s plan. At first Ananias was startled, not upon hearing the voice of the Lord, for apparently hearing that voice was not unfamiliar, but Ananias wondered about baptizing this Saul. Apparently, Ananias had heard of his coming with extradition papers from the high priest at Jerusalem for all believers found in Damascus (Acts 9:13-14). Nevertheless, Ananias was put at peace when the Lord told him Saul was to be one of his servants who would carry the Gospel to the gentiles. What news! Ananias was the first to witness the leopard lying down with the kid (Isaiah 11:6).
I wonder what it was like for Saul to partake of the Lord’s Supper for the first time. Did he partake with brethren in Damascus whom he had flogged in Jerusalem? What an emotional experience it must have been to be greeted by such brethren with a holy kiss (2Corinthians 13:2) as they shared together in memory of the Lord’s death (1Corinthians 11:26). What a powerful picture of the peace we all have in Christ!
In any event, Saul most likely wouldn’t have been able to offer much more than his personal testimony about meeting Jesus on that first visit. One cannot have one’s life turned upside down and not feel its affect emotionally, mentally and even physically. Saul has made his decision, but he also needed time to work all this out between himself and the Lord. He needed to study the Scriptures and understand just how all of it fit together and pointed to Jesus. Obviously, he had to unlearn the leaven of the Pharisaical teachings he had been taught and believed. Yet, the Gospel that Saul-Paul preached seems to be the same from Damascus to where he met his end in Rome decades later. Paul learned this Gospel in Arabia studying the Scriptures and led by the Spirit of Jesus as he observed Scriptural allegories from the Jews’ cousins in the land of Arabia.
 John Pollock makes an appropriate point in his book: The Apostle A Life of Paul, saying that an “historical pattern (is seen in that) great ambassadors for Christ, however prepared in other ways, are brought to their vocation by unimportant agents: Augustine hears a child’s voice repeat ‘Take up and read!’ John Wesley listens to an anonymous Moravian reading Luther; D.L. Moody, wrapping up shoes in a store, pauses for a few words from his Sunday School teacher; Charles Haddon Spurgeon, sheltering from a snowstorm, hears a workingman in a snowbound minister’s pulpit.”