The Supreme Authority of the Roman Pontiff

[Lorenzo]

First Vatican Council (1870):

"the Roman Pontiff, when he speaks ex cathedra -- that is, when in the exercise of his office as pastor and teacher of all Christians he defines, by virtue of his supreme Apostolic authority, a doctrine of faith or morals to be held by the whole Church -- is, by reason of the Divine assistance promised to him in blessed Peter, possessed of that infallibility with which the Divine Redeemer wished His Church to be endowed in defining doctrines of faith and morals; and consequently that such definitions of the Roman Pontiff are irreformable of their own nature (ex sese) and not by reason of the Church's consent".

[Lorenzo]

"This consideration too clarifies the great error of those others as well who boldly venture to explain and interpret the words of God by their own judgment, misusing their reason and holding the opinion that these words are like a human work. God Himself has set up a living authority to establish and teach the true and legitimate meaning of His heavenly revelation. This authority judges infallibly all disputes which concern matters of faith and morals, lest the faithful be swirled around by every wind of doctrine which springs from the evilness of men in encompassing error. And this living infallible authority is active only in that Church which was built by Christ the Lord upon Peter, the head of the entire Church, leader and shepherd, whose faith He promised would never fail. This Church has had an unbroken line of succession from Peter himself; these legitimate pontiffs are the heirs and defenders of the same teaching, rank, office and power. And the Church is where Peter is, and Peter speaks in the Roman Pontiff, living at all times in his successors and making judgment, providing the truth of the faith to those who seek it. The divine words therefore mean what this Roman See of the most blessed Peter holds and has held."

[Lorenzo]

For this mother and teacher of all the churches has always preserved entire and unharmed the faith entrusted to it by Christ the Lord. Furthermore, it has taught it to the faithful, showing all men truth and the path of salvation. Since all priesthood originates in this church, the entire substance of the Christian religion resides there also. The leadership of the Apostolic See has always been active, and therefore because of its preeminent authority, the whole Church must agree with it. The faithful who live in every place constitute the whole Church. Whoever does not gather with this Church scatters.
We, therefore, placed inscrutably by God upon this Chair of truth, eagerly call forth in the Lord your outstanding piety, venerable brothers. We urge you to strive carefully and zealously to continually warn and exhort the faithful entrusted to your care to hold to these first principles. Urge them never to allow themselves to be deceived and led into error by men who have become abominable in their pursuits. These men attempt to destroy faith on the pretext of human progress, subjecting it in an impious manner to reason and changing the meaning of the words of God. Such men do not shrink from the greatest insults to God Himself, who cares for the good and the salvation of men by means of His heavenly religion."