The Vatican Council
Fourth Session 
FIRST DOGMATIC CONSTITUTION ON THE CHURCH OF CHRIST - July 18th, 1870
Pius, bishop, servant of the servants of God, with the approval of the sacred council, for an everlasting record. The eternal shepherd and guardian of our souls [37] , in order to render permanent the saving work of redemption, determined to build a church in which, as in the house of the living God, all the faithful should be linked by the bond of one faith and charity. Therefore, before he was glorified, he besought his Father, not for the apostles only, but also for those who were to believe in him through their word, that they all might be one as the Son himself and the Father are one [38] . So then, just as he sent apostles, whom he chose out of the world [39] , even as he had been sent by the Father [40], in like manner it was his will that in his church there should be shepherds and teachers until the end of time. In order, then, that the episcopal office should be one and undivided and that, by the union of the clergy, the whole multitude of believers should be held together in the unity of faith and communion, he set blessed Peter over the rest of the apostles and instituted in him the permanent principle of both unities and their visible foundation.
Upon the strength of this foundation was to be built the eternal temple, and the church whose topmost part reaches heaven was to rise upon the firmness of this foundation [41] . And since the gates of hell trying, if they can, to overthrow the church, make their assault with a hatred that increases day by day against its divinely laid foundation, we judge it necessary, with the approbation of the sacred council, and for the protection, defence and growth of the catholic flock, to propound the doctrine concerning the institution, permanence and nature of the sacred and apostolic primacy, upon which the strength and coherence of the whole church depends.
This doctrine is to be believed and held by all the faithful in accordance with the ancient and unchanging faith of the whole church. Furthermore, we shall proscribe and condemn the contrary errors which are so harmful to the Lord's flock.
37. 1 Pt 2,25
38. Jn 17, 20-21
39. Jn 15, 19
40. Jn 20, 21
41. Leo 1, Serm. (Sermons), 4 (elsewhere 3), ch. 2 for the day of his birth (PL 54, 150).