Of the infallible Authm-iti/ of the Roman Pontiff in Teach- inrj. — This holy see hath ever held — the uubrokeu custom of the Church doth prove — and the oecumenical councils, those especially in which the East joined with the West in union of faith and of charity, have declared, that in this apostolic primacy, which the Roman pontiff holds over the universal Church as successor of Peter, the prince of the apostles, there is also contained the supreme power of authoritative teaching. Thus the fathers of the fourth Council of Constantinople, following in the footsteps of their predecessors, put forth this solemn profession :
"The tirst law of salvation is to keep the rule of true faith. And whereas the words of our Lord Jesus Christ cannot be passed bv, who said, Thou art Peter, and upon this rock I will hiiild my Church (Matt, xvi, 18), these words, which he spake, art proved true hy facts; for in the apostolic see the Catholic religion has ever been pre- served unspotted, and the holy doctrine has been an- nounced. Therefore, wishing never to be separated from the faith and teaching of this see, we hope to be worthy to abide in that one communion which the apostolic see l)reaches, in M'hich is the full and true tirniness of the Christian religion." [Formula of St. Hormisdas, pope, a* proposed by Iladiiau II to the fathers of the eighth j General Council (Constantinople, IV), and subscribed by \ them.]
So, too, the Greeks, with the approval of the second Council of Lyons, professed that the holy Rcmiau Church holds over the universal Catholic Church a supreme and fall primacy and headship, which she truthfully and hum- bly acknowledges that she received, with fulness of pow- er, from the Lord himself in blessed Peter, the prince or head of the apostles, of whom the Roman pontifl'is the successor ; and as she, heyond the others, is bound to de- fend the truth of the faith, so, if any questions arise con- cerning faith, they should he decided hy her judgment. And, tinally, the Council of Florence defined that the Ro- man pontiff is the true vicarof Christ, and the head of the whole Church, and the father and teacher of all Christians, and that to him, in the blessed Peter, was <:iven by our Lord Jesus Clirist full jiower of iV'eding, and ruling", and govei'ninir the univiTsal Church (John x.xi, 15-17).
In order to fulfil this pastoral charge, our predecessors have evt-r labored unweariedly to spread the saving doc- trine of Christ among all the nations of the earth, and with equal care have watched to preserve it pure and un- changed where it had been received. Wherefore the bish- ops of the whole world, sometimes singly, sometimes as- sembled in synods, following the long-established custom of the churches (St. Cyril, Alexand., and St. Cosiest. Pap.), and the form of ancient rule (St. Innocent I to Councils of Carthage and Milevi), referred to this apostolic see those dangers especially which arose in matters of faith, in order that injuries to faith might best be healed there where the faith could never fail (St. Bernard, epistli 190). And the Roman pontiffs, weighing the condition of times and circumstances, sometimes calling together general councils, or asking the judgment of the Church scattered through the world, sometimes consulting particular svn- ods, .-ometimes using such other aids as divine Providence supplied, defined that those doctrines should be held which, by the aid of God, they knew to be conformable to the holy Scriptures and the apostolic traditions. For the Holy Ghost is not promised to the successors of Peter, that they may make known new doctrine revealed by him, hut that, through his assistance, they mav sacredly guard and faithfully set forth the revelation delivered by the apostles, that is, the deposit of faith. And this their apostolic teaching all the venerable fathers have em- braced, and the holy orthodox doctors have revered and followed, knowing most certainly that this see of St. Pe- ter ever remains free from all error, according to the di- vine promise of our Lord and Saviour made to the prince
of the apostles : I have prayed for thee that thy faith fail not, and thou, beintr once converted, confirm thy brethren. (Conf. St. ALratho, Ep.<vt Imp. a Cone. Qicum.VIapprnb.)
'riiciefori'tliis gift of truth, and of faith which fails not, was divinely liestowcd on Peter and his successors in this chair, that they sliould exercise their high oftice for the salvation of all, that thrcnigh them the universal flock of Christ slnudd lie turned away from the poisonotis food of error and should be nourished with the food of heavenly doctrine, and that, the occasion of schism being removed, the entire Church should be preserved one, and, planted on her foundation, should stand firm against the gates of hell.
Nevertheless, since in this present age, when the saving efficacy of the apostolic office is exceedingly needed, there are not a few who carp at its authority, we judge it al- together necessary to solemnly declare the prerogative which the only-begotten SonofGodhas designed to unite to the sui)reme pastoral office.
Wherefore, faithfully adhering to the tradition handed down from the commencement of the Christian faith, for the glory of God our Saviour, the exaltation of the Catho- lic religion, and the salvation of Christian peoples, with the approbation of the sacred council, we teach and define it to be a doctrine divinely revealed, that, when the Ro- man pontiff speaks ex cathedra, that is, when in the exer- cise of his office of pastor and teacher of all Christians, and in virtue of his supreme apostolic authority, he de- fines that a doctrine of faith or morals is to be held hy the universal Church, he possesses, through the divine assist- ance promised to him in the blessed Peter, that infallibil- ity with which the divine Redeemer willed his Church to be endowed, in defining a doctrine of faith and morals; and therefore that such definitions of the Roman pontiff are irreformable of themselves, and not by force of the consent of the Church thereto.