The common faith of the members of Christ is most intimately bound up with their priestly fellowship in prayer. The Catholic fellowship in faith does not mean merely that all the members of the Church loyally profess one and the same faith, presented to them by apostolic authority, that they share the same luminous ideal, the same effective rule and the same fruitful sources of spiritual life. It means more than that. It means that there is a solidarity and partnership of the faith, a reciprocal interaction and fruitful influence, which by intimate and pervasive action make their external union an inward communion in the faith, a communion which out of the depths of the common experience of the faith is ever expressing itself anew in a single “credo” of the mystical Christ.