{Proclaimed} (kat(8867)gellon). Imperfect active of
kataggell(935c), inchoative, began to proclaim. This was Paul's rule
of procedure, "to the Jew first" ( Ro 1:16  Ac 13:46  17:2  18:4,19  19:8 ). {They had also} (eichon de kai). Imperfect
active, descriptive. {As their attendant} (hup(8872)et(886e)).
Literally, "under-rower" (hupo, (8872)et(8873)) in the trireme.
Probably here minister (chazzan) or assistant in the synagogue
as in  Lu 4:20 . Cf.  Mt 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 (verse  13 ). The "also" may mean that Mark
did some preaching. Barnabas was probably the leader in the work
in these Jewish synagogues.