Paul and Barnabas separated, and Paul chose Silas.

Acts 15:36-41

36 After some time Paul said to Barnabas, “Let’s go back and visit the fellow believers in every city where we previously proclaimed the message about the Lord Jesus. In that way, we will know how well they are continuing to believe in the Lord Jesus.” 37 Barnabas agreed with Paul, and said that he wanted to take John, whose other name was Mark, along with them again. 38 However, Paul told Barnabas that he thought that it would not be good to take Mark with them, because Mark had deserted them when they were previously in Pamphylia region, and had not continued to work with them. 39 Paul and Barnabas strongly disagreed with each other about that, so they separated. Barnabas took Mark along with him and they got on a ship and went to Cyprus. 40 Paul chose Silas, who had returned to Antioch, to work with him. The believers there asked the Lord God to graciously help Paul and Silas. Then the two of them departed from Antioch. 41 Paul continued traveling with Silas through Syria and Cilicia provinces. In those places he was helping the congregations to trust strongly in the Lord Jesus.