Glossa Ordinaria

James. He undertook the care and governance of the church of Jerusalem, after the apostles had been sent out to preach. To the twelve tribes. To have particular concern for these belonged to the twelve apostles, who discharged an embassy for the Lord among the circumcision. Whence Paul also says: James, and Cephas, and John, who seemed to be pillars, gave the right hands, etc. Therefore he writes to them especially, and because he himself had been ordained bishop over them by the rest of the apostles.