This was Saul's first mission trip but it wasn't the first in history. There were several places he went where a few people had already heard about Jesus. The church was getting larger and larger and filled with strong men of God. When Saul and Barnabas heard the call from the Lord they were at church surrounded by other believers. The congregation celebrated with them and before they sent them off they laid hands on them and prayed over them for guidance and protection.
The men begin their journey in Cypress where they are quick to preach and shows the truths of the Lord. When word got out to the governor, Sergius Paulus, he sent for them so to learn more about what they were teaching. While they were there a magician named Bar-Jesus wanted to disprove them and turn others away from the faith. Saul, now known as Paul, looked at him and with the power of the Lord spoke what was being revealed to him. He knew that this man was speaking lies and was full of deceit. Immediately the Lord used Paul to bring blindness to the man and he had to be helped out of the building. Because of all this the governor was quick to believe and became a follower of the Lord.
Here we have record of Paul's first sermon even though this wasn't really his first. He begins by recapping the history of Moses and the lives of many other lives that are so important because of how they help shape the line of followers. He tells the people that they are freed from their sin because of Jesus not because of the Law of Moses. There were many who heard but rejected due to their jealousy. Even though this probably came as a shock to the men they must go through those times in order to strengthen in Him. All they could really do was dust off their feet and move on.