In this state of matters the Church of Rome, the proceedings of which are known to us through Irenæus and Tertullian, took, with regard to the fixed Roman baptismal confession ascribed to the Apostles, the following step: The Antignostic interpretation required by the necessities of the times was proclaimed as its self-evident content; the confession, thus explained, was designated as the "Catholic faith" ("fides catholica"), that is the rule of truth for the faith; and its acceptance was made the test of adherence to the Roman Church as well as to the general confederation of Christendom. Irenæus was not the author of this proceeding. How far Rome acted with the coöperation or under the influence of the Church of Asia Minor is a matter that is still obscure,[34] and will probably never be determined with certainty. What the Roman community accomplished practically was theoretically established by Irenæus[35] and Tertullian. The former proclaimed the baptismal confession, definitely interpreted and expressed in an Antignostic form, to be the apostolic rule of truth (regula veritatis), and tried to prove it so. He based his demonstration on the theory that this series of doctrines embodied the faith of the churches founded by the Apostles, and that these communities had always preserved the apostolic teaching unchanged (see under C).
Viewed historically, this thesis, which preserved Christianity from complete dissolution, is based on two unproved assumptions and on a confusion of ideas. It is not demonstrated that any creed emanated from the Apostles, nor that the Churches they founded always preserved their teaching in its original form; the creed itself, moreover, is confused with its interpretation. Finally, the existence of a fides catholica, in the strict sense of the word, cannot be justly inferred from the essential agreement found in the doctrine of a series of communities.[36] But, on the other hand, the course taken by Irenæus was the only one capable of saving what yet remained of primitive Christianity, and that is its historical justification. A fides apostolica had to be set up and declared identical with the already existing fides catholica. It had to be made the standard for judging all particular doctrinal opinions, that it might be determined whether they were admissible or not.
The persuasive power with which Irenæus set up the principle of the apostolic "rule of truth," or of "tradition" or simply of "faith," was undoubtedly, as far as he himself was concerned, based on the facts that he had already a rigidly formulated creed before him and that he had no doubt as to its interpretation.[37] The rule of truth (also 'η 'υπο της εκκλησιας κηρυσσομενη αληθεια "the truth proclaimed by the Church;" and το της αληθειας σωματιον, "the body of the truth") is the old baptismal confession well known to the communities for which he immediately writes. (See I. 9. 4; 'ουτω δε και 'ο τον κανονα της αληθειας ακλινη εν 'εαυτω κατεχων 'ον δια του βαπτισματος ειληφε, "in like manner he also who retains immovably in his heart the rule of truth which he received through baptism"); because it is this, it is apostolic, firm and immovable.[38]
By the fixing of the rule of truth, the formulation of which in the case of Irenæus (I. 10. 1, 2) naturally follows the arrangement of the (Roman) baptismal confession, the most important Gnostic theses were at once set aside and their antitheses established as apostolic. In his apostolic rule of truth Irenæus himself already gave prominence to the following doctrines:[39] the unity of God, the identity of the supreme God with the Creator; the identity of the supreme God with the God of the Old Testament; the unity of Jesus Christ as the Son of the God who created the world; the essential divinity of Christ; the incarnation of the Son of God; the prediction of the entire history of Jesus through the Holy Spirit in the Old Testament; the reality of that history; the bodily reception (ενσαρκος αναληψις) of Christ into heaven; the visible return of Christ; the resurrection of all flesh (αναστασις πασης σαρκος, πασης ανθροπωτητος), the universal judgment. These dogmas, the antitheses of the Gnostic regulæ,[40] were consequently, as apostolic and therefore also as Catholic, removed beyond all discussion.
Tertullian followed Irenæus in every particular. He also interpreted the (Romish) baptismal confession, represented it, thus explained, as the regula fidei,[41] and transferred to the latter the attributes of the confession, viz., its apostolic origin (or origin from Christ), as well as its fixedness and completeness.[42] Like Irenæus, though still more stringently, he also endeavoured to prove that the formula had descended from Christ, that is, from the Apostles, and was incorrupt. He based his demonstration on the alleged incontestable facts that it contained the faith of those Churches founded by the Apostles, that in these communities a corruption of doctrine was inconceivable, because in them, as could be proved, the Apostles had always had successors, and that the other Churches were in communion with them (see under C). In a more definite way than Irenæus, Tertullian conceives the rule of faith as a rule for the faith,[43] as the law given to faith,[44] also as a "regula doctrinæ" or "doctrina regulæ" (here the creed itself is quite plainly the regula), and even simply as "doctrina" or "institutio."[45] As to the content of the regula, it was set forth by Tertullian in three passages.[46] It is essentially the same as in Irenæus. But Tertullian already gives prominence within the regula to the creation of the universe out of nothing,[47] the creative instrumentality of the Logos,[48] his origin before all creatures,[49] a definite theory of the Incarnation,[50] the preaching by Christ of a nova lex and a nova promissio regni cœlorum,[51] and finally also the Trinitarian economy of God.[52] Materially, therefore, the advance beyond Irenæus is already very significant. Tertullian's regula is in point of fact a doctrina. In attempting to bind the communities to this he represents them as schools.[53] The apostolic "lex et doctrina" is to be regarded as inviolable by every Christian. Assent to it decides the Christian character of the individual. Thus the Christian disposition and life come to be a matter which is separate from this and subject to particular conditions. In this way the essence of religion was split up—the most fatal turning-point in the history of Christianity.
But we are not of course to suppose that at the beginning of the third century the actual bond of union between all the Churches was a fixed confession developed into a doctrine, that is, definitely interpreted. This much was gained, as is clear from the treatise de præscriptione and from other evidence, that in the communities with which Tertullian was acquainted, mutual recognition and brotherly intercourse were made to depend on assent to formulæ which virtually coincided with the Roman baptismal confession. Whoever assented to such a formula was regarded as a Christian brother, and was entitled to the salutation of peace, the name of brother, and hospitality.[54] In so far as Christians confined themselves to a doctrinal formula which they, however, strictly applied, the adoption of this practice betokened an advance. The scattered communities now possessed a "lex" to bind them together, quite as certainly as the philosophic schools possessed a bond of union of a real and practical character[55] in the shape of certain briefly formulated doctrines. In virtue of the common apostolic lex of Christians the Catholic Church became a reality, and was at the same time clearly marked off from the heretic sects. But more than this was gained, in so far as the Antignostic interpretation of the formula, and consequently a "doctrine," was indeed in some measure involved in the lex. The extent to which this was the case depended, of course, on the individual community or its leaders. All Gnostics could not be excluded by the wording of the confession; and, on the other hand, every formulated faith leads to a formulated doctrine, as soon as it is set up as a critical canon. What we observe in Irenæus and Tertullian must have everywhere taken place in a greater or less degree; that is to say, the authority of the confessional formula must have been extended to statements not found in the formula itself.
We can still prove from the works of Clement of Alexandria that a confession claiming to be an apostolic law of faith,[56] ostensibly comprehending the whole essence of Christianity, was not set up in the different provincial Churches at one and the same time. From this it is clearly manifest that at this period the Alexandrian Church neither possessed a baptismal confession similar to that of Rome,[57] nor understood by "regula fidei" and synonymous expressions a collection of beliefs fixed in some fashion and derived from the apostles.[58] Clement of Alexandria in his Stromateis appeals to the holy (divine) Scriptures, to the teaching of the Lord,[59] and to the standard tradition which he designates by a great variety of names, though he never gives its content, because he regards the whole of Christianity in its present condition as needing to be reconstructed by gnosis, and therefore as coming under the head of tradition.[60] In one respect therefore, as compared with Irenæus and Tertullian, he to some extent represents an earlier standpoint; he stands midway between them and Justin. From this author he is chiefly distinguished by the fact that he employs sacred Christian writings as well as the Old Testament, makes the true Gnostic quite as dependent on the former as on the latter and has lost that naive view of tradition, that is, the complete content of Christianity, which Irenæus and Tertullian still had. As is to be expected, Clement too assigns the ultimate authorship of the tradition to the Apostles; but it is characteristic that he neither does this of such set purpose as Irenæus and Tertullian, nor thinks it necessary to prove that the Church had presented the apostolic tradition intact. But as he did not extract from the tradition a fixed complex of fundamental propositions, so also he failed to recognise the importance of its publicity and catholicity, and rather placed an esoteric alongside of an exoteric tradition. Although, like Irenæus and Tertullian, his attitude is throughout determined by opposition to the Gnostics and Marcion, he supposes it possible to refute them by giving to the Holy Scriptures a scientific exposition which must not oppose the κανων της εκκλησιας, that is, the Christian common sense, but receives from it only certain guiding rules. But this attitude of Clement would be simply inconceivable if the Alexandrian Church of his time had already employed the fixed standard applied in those of Rome, Carthage and Lyons.[61] Such a standard did not exist; but Clement made no distinction in the yet unsystematised tradition, even between faith and discipline, because as a theologian he was not able to identify himself with any single article of it without hesitation, and because he ascribed to the true Gnostic the ability to fix and guarantee the truth of Christian doctrine.
Origen, although he also attempted to refute the heretics chiefly by a scientific exegesis of the Holy Scriptures, exhibits an attitude which is already more akin to that of Irenæus and Tertullian than to that of Clement. In the preface to his great work, "De principiis," he prefixed the Church doctrine as a detailed apostolic rule of faith, and in other instances also he appealed to the apostolic teaching.[62] It may be assumed that in the time of Caracalla and Heliogabalus the Alexandrian Christians had also begun to adopt the principles acted upon in Rome and other communities.[63] The Syrian Churches, or at least a part of them, followed still later.[64] There can be no doubt that, from the last decades of the third century onward, one and the same confession, identical not in its wording, but in its main features, prevailed in the great confederation of Churches extending from Spain to the Euphrates and from Egypt to beyond the Alps.[65] It was the basis of the confederation, and therefore also a passport, mark of recognition, etc., for the orthodox Christians. The interpretation of this confession was fixed in certain ground features, that is, in an Antignostic sense. But a definite theological interpretation was also more and more enforced. By the end of the third century there can no longer have been any considerable number of outlying communities where the doctrines of the pre-existence of Christ and the identity of this pre-existent One with the divine Logos were not recognised as the orthodox belief.[66] They may have first become an "apostolic confession of faith" through the Nicene Creed. But even this creed was not adopted all at once.
B. The designation of selected writings read in the churches as New Testament Scriptures or, in other words, as a collection of apostolic writings.[67]
Every word and every writing which testified of the κυριος (Lord) was originally regarded as emanating from him, that is, from his spirit: 'Οθεν 'η κυριοτης λαλειται εκει Κυριος εστιν. (Didache IV. 1; see also 1 Cor. XII. 3). Hence the contents were holy.[68] In this sense the New Testament is a "residuary product," just as the idea of its inspiration is a remnant of a much broader view. But on the other hand, the New Testament is a new creation of the Church,[69] inasmuch as it takes its place alongside of the Old—which through it has become a complicated book for Christendom,—as a Catholic and apostolic collection of Scriptures containing and attesting the truth.