The Commonitory of Vincent of Lérins, For the Antiquity and Universality of the Catholic Faith Against the Profane Novelties of All Heresies 3
3 Chapter III. What is to be done if one or more dissent from the rest PL 50, 640
What is to be done if one or more dissent from the rest.
[7.] What then will a Catholic Christian do, if a small portion of the Church have cut itself off from the communion of the universal faith? What, surely, but prefer the soundness of the whole body to the unsoundness of a pestilent and corrupt member? What, if some novel contagion seek to infect not merely an insignificant portion of the Church, but the whole? Then it will be his care to cleave to antiquity, which at this day cannot possibly be seduced by any fraud of novelty.
[8.] But what, if in antiquity itself there be found error on the part of two or three men, or at any rate of a city or even of a province? Then it will be his care by all means, to prefer the decrees, if such there be, of an ancient General Council to the rashness and ignorance of a few. But what, if some error should spring up on which no such decree is found to bear? Then he must collate and consult and interrogate the opinions of the ancients, of those, namely, who, though living in divers times and places, yet continuing in the communion and faith of the one Catholic Church, stand forth acknowledged and approved authorities: and whatsoever he shall ascertain to have been held, written, taught, not by one or two of these only, but by all, equally, with one consent, openly, frequently, persistently, that he must understand that he himself also is to believe without any doubt or hesitation.
Quid igitur tunc faciet Christianus catholicus, si se aliqua Ecclesiae particula ab universalis fidei communione praeciderit? Quid utique nisi ut pestifero corruptoque membro sanitatem universi corporis anteponat? Quid si novella aliqua contagio non jam portiunculam tantum, sed totam pariter Ecclesiam commaculare conetur? Tunc item providebit ut antiquitati inhaereat, quae prorsum jam non potest ab ulla novitatis fraude seduci. Quid si in ipsa vetustate, duorum aut trium hominum, vel certe civitatis unius aut etiam provinciae alicujus error deprehendatur? Tunc omnino curabit ut paucorum temeritati vel inscitiae, si qua sunt, universaliter antiquitus universalis Ecclesiae decreta praeponat. Quid si tale aliquid emergat ubi nihil hujusmodi reperiatur? Tunc operam dabit ut collatas inter se majorum consulat interrogetque sententias, eorum duntaxat qui diversis licet temporibus et locis, in unius tamen Ecclesiae Catholicae communione et fide permanentes, magistri probabiles exstiterunt; et quicquid non unus aut duo tantum, sed omnes pariter uno eodemque consensu aperte, frequenter, perseveranter tenuisse, scripsisse, docuisse cognoverit, id sibi quoque intelligat absque ulla dubitatione credendum.