Albert Barnes on Acts 11:25

Then departed, etc. Why Barnabas sought Saul, is not known. It is probable, however, that it was owing to the remarkable success which he had in Antioch. There was a great revival of religion; and there was need of additional labour. In such scenes the ministers of the gospel need additional help, as men in harvest-time seek the aid of others. Saul was in this vicinity, Acts 9:30 and he was eminently fitted to aid in this work. With him Barnabas was well acquainted, Acts 9:27 and probably there was no other one in that vicinity whom he could obtain.

To Tarsus. Acts 9:11.

(l) "departed Barnabas" Acts 9:27,30