The same admirable unity that exists in matters of faith is also established in the government of the Church. All the members of the vast body of Catholic Christians are as intimately united to one visible Chief as the members of the human body are joined to the head. The faithful of each Parish are subject to their immediate Pastor. Each Pastor is subordinate to his Bishop, and each Bishop of Christendom acknowledges the jurisdiction of the Bishop of Rome, the successor of St. Peter, and Head of the Catholic Church. But it may be asked, is not this unity of faith impaired by those doctrinal definitions which the Church has promulgated from time to time? We answer: No new dogma, unknown to the Apostles, not contained in the primitive Christian revelation, can be admitted. (John xiv. 26; xv. 15; xvi. 13.) For the Apostles received the whole deposit of God’s word, according to the promise of our Lord: “When He shall come, the Spirit of truth, He shall teach you all truth.” And so the Church proposes the doctrines of faith, such as came from the lips of Christ, and as the Holy Spirit taught them to the Apostles at the birth of the Christian law—doctrines which know neither variation nor decay. Hence, whenever it has been defined that any point of doctrine pertained to the Catholic faith, it was always understood that this was equivalent to the declaration that the doctrine in question had been revealed to the Apostles, and had come down to us from them, either by Scripture or tradition. And as the acts of all the Councils, and the history of every definition of faith evidently show, it was never contended that a _new revelation_ had been made, but every inquiry was directed to this one point—whether the doctrine in question was contained in the Sacred Scriptures or in the Apostolic traditions. A revealed truth frequently has a very extensive scope, and is directed against error under its many changing forms. Nor is it necessary that those who receive this revelation in the first instance should be explicitly acquainted with its full import, or cognizant of all its bearings. Truth never changes; it is the same now, yesterday, and forever, _in itself_; but our relations towards truth may change, for that which is hidden from us today may become known to us tomorrow. “It often happens,” says St. Augustine, “that when it becomes necessary to defend certain points of Catholic doctrine against the insidious attacks of heretics they are more carefully studied, they become _more clearly understood_, they are _more earnestly inculcated_; and so the very questions raised by heretics give occasion to a more thorough knowledge of the subject in question.”(29)