and when they were at Salamis - the Grecian capital of the island, on the eastern side, and not many hours’ sail from Seleucia. At this busy mercantile port immense numbers of Jews were settled, which accounts for what is here said, that they had more than one synagogue, in which Barnabas and Saul preached, while other cities had one only.
they had ... John - Mark.
to their minister - “for their officer“. (See on Luk 4:20). With what fruit they preached here is not said. Probably their feeling was what Paul afterwards expressed at Antioch in Pisidia (Act 13:46).