These things being as they are, it is evident that the Apostolic See can have no part in their meetings by any league--pactum--nor is it lawful for Catholics by any league to support such undertakings and give them aid. For, if they should do so, they would be giving countenance to a false Christian religion, quite alien to the one Church of Christ. Shall We suffer,--what would indeed be iniquitous--the truth, and that truth divinely revealed, to be drawn out by agreements? For here the question is one of defending revealed truth. Jesus Christ sent the Apostles into the whole world to imbue all nations with the Gospel faith and, lest they should err, he willed beforehand that they should be taught by the Holy Ghost--John xvi, 13. Has then this doctrine of the Apostles completely vanished away, or at times been corrupted in the Church whose ruler and guardian, God Himself is with us? If our Redeemer plainly taught that His Gospel was to hold not only during the times of the Apostles, but also to after ages, is it possible that the object of faith should in the process of time become so obscure and uncertain that it would be necessary today to tolerate opinions which are even contrary one to the other? If this were true, we should have also to say that the coming of the Holy Ghost on the Apostles and the perpetual indwelling of the same Spirit in the Church, yea the preaching of Jesus Christ itself a number of centuries ago, lost all their efficacy and use--to affirm which would be blasphemy. But the Only-begotten Son of God, when he commanded his representatives to teach all nations, bound all men to give credence to whatever was made known to them by the witnesses preordained by God, Acts x, 21, and he also confirmed his command with this sanction: He that believeth and is baptized shall be saved; but he that believeth not shall be condemned, Mk. xvi, 18. These two commands of Christ, which must be certainly fulfilled, the one, namely, to teach and the other to believe unto the reception of salvation, cannot be understood, unless the Church proposes a complete and easily understood teaching and is immune, when it thus teaches, from all danger of erring. In this matter, those also turn aside from the right path, who think that while the deposit of truth does indeed exist, it must be sought with such laborious trouble and with such daily study and reasonings that a man's term of life would hardly suffice to find it out and grasp it; as if the most merciful God has so spoken through the prophets and His only-begotten Son that only a few, and those stricken in years, could learn what He had revealed through them, and not that He might inculcate that doctrine of faith and morals, by which man is to be guided through the whole course of his moral life.
These pan-Christians who turn their minds to uniting churches,-consociandas ecclesias --seem indeed, to be pursuing the noblest plans in promoting love among all Christians; nevertheless, how shall it happen that this love inures to the injury of the faith? Certainly, no one is ignorant that John himself, the Apostle of love, who seems to reveal in his Gospel the secrets of the most Sacred Heart of Jesus, and never ceased to impress on the memories of his followers the new commandment 'Love one another,' altogether forbade any intercourse with those who professed a partial and corrupt version of Christ's teaching, If any man come to you and bring not this doctrine, receive him not into the house nor say to him: God speed you, II John x. For which reason, since love is based on a complete and sincere faith, as its foundation, the disciples of Christ must be bound together by one faith as the principal bond. Who then can conceive any Christian Federation--foedus--members of which retain each his own opinions and private judgment, yea in matters which concern the object of faith, even though their opinions be repugnant to the opinions of the rest? And by what sort of league--pacto--We ask, can men who go off into opposing opinions, belong to one and the same Federation of the faithful? For example, those who affirm, and those who deny that sacred Tradition is a true font of divine Revelation; those who hold that an ecclesiastical hierarchy, made up of bishops, priests and ministers, has been divinely constituted, and those who assert that it has been brought in little by little through the conditions of the time; those who adore Christ really present in the Most Holy Eucharist by that marvellous conversion of the bread and wine, called transubstantiation and adore him really as present and those who affirm that Christ is present only by faith, or symbolically and virtually in the Sacrament; those who in the Eucharist recognize the nature both of a sacrament and of a sacrifice, and those who say that it is nothing more than the memorial or (commemoration of the Lord's Supper; those who believe it to be good and useful to invoke by prayer the Saints reigning with Christ, especially Mary the Mother of God, and to venerate their images, and those urge that such worship is not to be employed since it is contrary to the honour due to Jesus Christ, 'the one mediator of God and men.' I Tim. ii, 5. How so great a discrepancy of opinions can make the way clear to effect the unity of the Church, We know not; since that unity can not arise except from one teaching authority, one law of belief and one faith of Christians. But, We do know that from this, it is an easy step to the neglect of religion or indifferentism and to modernism, as they call it. For those who are unhappily infected with these errors hold that dogmatic truth is not absolute but relative, that is, it adapts itself to the varying necessities of time and place and to the varying tendencies of the mind, since it is not contained in immutable revelation but is of such a nature that it accommodates itself to the life of men. Besides this, in connection with things which must be believed, it is nowise lawful to use that distinction which some have seen fit to introduce between fundamental and non-fundamental articles of faith, as they call them, as if the one are to be accepted by all while the other may be left free to the assent of the faithful. For the supernatural virtue of faith has a formal cause, namely the authority of God the revealer, and this authority admits of no such distinction. For this reason all who are truly Christ's believe, for example, the Conception of the Mother of God without stain of original sin with the same faith as they believe the mystery of the August Trinity and, likewise, the Incarnation of the Lord no otherwise than they believe the infallible teaching authority of the Roman Pontiff, according to the sense in which it was defined by the Ecumenical Council of the Vatican. Are such truths not equally certain or not equally to be believed, because the Church has solemnly sanctioned and defined them, some in one age and some in another, yea, even in those times immediately before our own? Has not God revealed them all? For the teaching authority of the Church, which in the divine plan was constituted on earth in order that revealed doctrines might remain intact for ever and that they might be brought easily and safely to the knowledge of men, as that authority is exercised daily by the Roman Pontiff and the Bishops in communion with him and has for its office--in case it is necessary to resist more vigorously the errors and attacks of heretics or explain more clearly and deeply the articles of the sacred doctrine and impress them upon the minds of the faithful--to proceed at the proper times to make definitions either by solemn rites or decrees. However, in the use of this extraordinary teaching authority--magisterium--nothing newly discovered is introduced nor is anything new added to the sum of those truths which are at least implicitly--saltem implicite--contained in the deposit of Revelation, divinely handed down to the Church, but those things are declared which perhaps had seemed to many obscure or those things ordered to be held which by some had been regarded as matter of controversy.
Therefore, Venerable Brethren, it is evident why this Apostolic See has never allowed its own to take part in the meetings of non-Catholics, for the union of Christians can hardly be promoted otherwise than by promoting the return of the dissidents to Christ's one true Church, inasmuch as in the past they unhappily revolted--descivere--from her, yea Christ's one true Church,--We say,--which is clearly manifest--conspicuam--to all and by the will of her Author will so remain forever as He himself instituted it for our common salvation. For during the lapse of the centuries Christ's mystical Bride has never been contaminated nor can she be contaminated, as was said by Cyprian, 'Christ's Bride can never be adulterated; she is incorrupt and modest. She knows one dwelling and in chaste modesty guards the sanctity of one bedchamber,' de cath. eccl. unitate, 6. And the same holy Martyr with good reason marvelled greatly that any one could possibly believe that 'this unity, proceeding from the divine foundation and knit together by the heavenly sacraments might be rent in the church and torn apart by divorce through wills in collision.' For, since Christ's mystical body, that is the Church, is one being compacted together and conjoined, Eph. iv, 16, as is for example the physical body, I Cor. xii, 12, one speaks indiscreetly and foolishly who says that the mystical body can be made up of disjoined and scattered members. Whosoever, therefore, is not integrally connected with it--copulatur--is not a member of it nor is He joined with Christ, the head. Cp. Eph. v, 30; i, 22.
And, indeed, in this one Church of Christ there is no one and no one will continue to be except that, by giving his obedience, he acknowledges and accepts the authority and power of Peter and his legitimate successors. Did the ancestors of those who are ensnared in the errors of Photius and the modernists--novatorum--obey the Bishop of Rome, the supreme Pastor of souls? Alas, the sons left the paternal house but it did not on that account fall to pieces and perish, for it was upheld by God's perpetual and guardian care. Therefore, let them return to the common Father who forgetting the unjust injuries done to the Apostolic See, will accept them most affectionately. For if, as they continually are saying, they wish to be with Us and with ours, why do they not hasten to enter the Church, 'the mother and teacher of all Christ's faithful,'--Later. Counc. IV, c 5. Let them also hear Lactantius crying out, 'The Catholic Church is that alone which preserves the true worship. This is the font of truth, the house of the Faith, this the temple of God. If any one enter not therein or if any one go out therefrom, he is a stranger to the hope of life and salvation--a spe vitæ ac salutis alienus. No one should deceive himself with obstinate disputings. For here it is a question of life and salvation which are hopelessly lost unless they are dealt with advisedly and carefully.'--Div. Instt. lv, 30 11-12.
Let, therefore, the separated children draw nigh to the Apostolic See, set up in the City which Peter and Paul, the Princes of the Apostles, consecrated with their blood; to that See, We say, which is 'the root and matrix of the Catholic Church,' S. Cyprian, ep. 48 ad Cor., not with the purpose and the hope that 'the Church of the living God, the pillar and ground of the truth,' I Tim. iii, 15, will cast away the integrity of the faith and tolerate their errors, but, on the contrary, that they submit themselves to its teaching and government. Would that it were Our happy lot to do that which so many of Our predecessors could not do, namely, embrace with fatherly affection those whose lamentable separation from Us We now bewail. Would that God Our Saviour, 'Who will have all men to be saved and to come to the knowledge of the truth,' I Tim. ii, 4, would hear Us when We humbly beg that He would deign to recall to the Unity of the Church all who stray. In this most important undertaking We ask and wish that others should ask the interceder, Blessed Mary the Virgin, Mother of divine grace, Victor over all heresies and Help of Christians, that she may implore for Us the speedy coming of the much hoped for day, when all men shall hear the voice of her divine Son--'careful to keep the unity of the Spirit in the bond of peace,' Eph. iv, 3.