Now from[46] what has been said, it appears that Peter in Holy Scripture is set forth as the source and principle of ecclesiastical unity under a double but cognate image, as Foundation, and as Confirmer. Of the former we will here say nothing further, but a few consequences of the latter it is desirable here to group together. I. The unity, then, which consists in the profession of one and the same faith, is conspicuous among those[47] modes of unity by which Christ has willed that His Church should be distinguished. Now, first, S. Paul declares that the whole ministerial hierarchy, from the Apostolate downwards, was instituted by our Lord, for the sake of obtaining and preserving this unity. "He gave some Apostles, and some Prophets, and other some Evangelists, and other some pastors and doctors, for the perfecting" (literally, the fitting in together, the same word which S. Peter had used in his prayer, ch. v. 10,) "of the saints, for the work of the ministry, for the edifying of the body of Christ; until we all meet into the unity of faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the age of the fulness of Christ."[48] To this living hierarchy he expressly attributes preservation from doctrinal error, proceeding thus: "That henceforth we be no more children tossed to and fro, and carried about with every wind of doctrine by the wickedness of men, by cunning craftiness by which they lie in wait to deceive." And, secondly, this hierarchy itself was knitted and gathered up into a monarchy, and its whole force and solidity made to depend on association with Peter, to whom _alone_ was said, "But I have prayed for thee, that thy faith fail not;" to whom alone was enjoined, "And thou, in thy turn, one day confirm thy brethren."