Jamieson, Fausset and Brown on Acts 15:41

41. and he went through Syria and Cilicia, confirming the churches--"It is very likely that Paul and Barnabas made a deliberate and amicable arrangement to divide the region of their first mission between them; Paul taking the continental, and Barnabas the insular, part of the proposed visitation. If Barnabas visited Salamis and Paphos, and if Paul (travelling westward), after passing through Derbe, Lystra, and Iconium, went as far as Antioch in Pisidia, the whole circuit of the proposed visitation was actually accomplished, for it does not appear that any converts had been made at Perga and Attalia" [Howson]. "This second missionary tour appears to have proceeded at first solely from the desire of visiting the churches already planted. In the end, however, it took a much wider sweep, for it brought the apostle to Europe" [Olshausen].