Proclaimed (katēggellon). Imperfect active of kataggellō, inchoative, began to proclaim. This was Paul’s rule of procedure, “to the Jew first” (Rom 1:16; Act 13:46; Act 17:2; Act 18:4, Act 18:19; Act 19:8).
They had also (eichon de kai). Imperfect active, descriptive.
As their attendant (hupēretēn). Literally, “under-rower” (hupo, ēretēs) in the trireme. Probably here minister (chazzan) or assistant in the synagogue as in Luk 4:20. Cf. Mat 5:25. It is not clear what John Mark did, though he was evidently selected by Barnabas as his cousin. He may have helped in the baptizing. There were probably others also in the company (Act 13:13). The “also” may mean that Mark did some preaching. Barnabas was probably the leader in the work in these Jewish synagogues.