The correspondence between the Bishops of Tarracon and Pope Hilarius discusses significant issues concerning ecclesiastical discipline and the ordination of bishops. The bishops express concern over unauthorized ordinations and the potential for schism within the Church, specifically citing the actions of Bishop Silvanus. They call for adherence to the Nicene canons and divine law in the ordination process, asserting that only qualified individuals should be elevated to sacred orders. The letters also highlight the importance of unity and the authority of the apostolic see in maintaining ecclesiastical order.