I recently read the Commonitorium (c. AD 434) by Vincent of Lérins. The following are some interesting excerpts from the text (found in the Nicene Post-Nicene Fathers [series 2] volume 12 [a Latin text of the volume is available here]). A good volume on the theology of this book and its reception by John Henry Newman (1801-1890) is that of Thomas G. Guarino, Vincent of Lérins and the Development of Christian Doctrine (Grand Rapids, Mich.: Baker Academic, 2013)
Note how that, while Lérins did allow for some (organic) development in doctrines and held to a material (not formal) understanding of Scripture’s sufficiency, there is no “wriggle room” for Catholics to appeal to Lérins as there is no consistent way to use his writings as a “spring board” to support belief in dogmas such as the Immaculate Conception which was not an apostolic tradition by any stretch of the imagination:
Moreover, in the Catholic Church itself, all possible care must be taken, that we hold that faith which has been believed everywhere, always, by all. For that is truly and in the strictest sense “Catholic,” which, as the name itself and the reason of the thing declare, comprehends all universally. This rule we shall observe if we follow universality, antiquity, consent. We shall follow universality if we confess that one faith to be true, which the whole Church throughout the world confesses; antiquity, if we in no wise depart from those interpretations which it is manifest were notoriously held by our holy ancestors and fathers; consent, in like manner, if in antiquity itself we adhere to the consenting definitions and determinations of all, or at the least of almost all priests and doctors. (Chapter II, 6 [NPNF 2 XII:132])
To preach any doctrine therefore to Catholic Christians other than what they have received never was lawful, never is lawful, never will be lawful: and to anathematize those who preach anything other than what has once been received, always was a duty, always is a duty, always will be a duty. (Chapter IX, 25 [NPNF 2 XII:137])
Condemnation of “secret” traditions:
For thou mayest hear some of these same doctors say, “Come, O Silly wretches, who go by the name of Catholics, come and learn the true faith, which no one but ourselves is acquainted with, which same has lain hid these many ages, but has recently been revealed and made manifest. But learn it by stealth and in secret, for you will be delighted with it. Moreover, when you have learn it, teach it furtively, that the world may not hear, that the Church may not know. For there are but few of whom it is granted to receive the secret of so great a mystery.” Are not these the words of that harlot who, in the proverbs of Solomon, calls to the passengers who go right on their ways, “Whoso is simple let him turn in hither.” And as for them that are void of understanding, she exhorts them saying: “Drink stolen waters, for they are sweet and eat bread in secret for it is pleasant.” What next? “But he knoweth not that the sons of earth perish in her house.” Who are those “sons of earth”? Let the apostle explain: “Those who have erred concerning the faith.” (Chapter XXI, 52 [NPNF 2 XII:146-47])
But some one will say perhaps, Shall there, then, be no progress in Christ’s Church? Certainly; all possible progress. For what being is there, so envious of men, so full of hatred to God, who would seek to forbid it? Yet on condition that it be real progress, not alteration of the faith . . . that is to say, in the same doctrine, in the same sense, and in the same meaning. (Chapter XXIII, 54 [NPNF 2 XII:147-48])
There is a wide difference between the lower of youth and the maturity of age; yet they who were once young are still the same now that they have become old, insomuch that though the stature and outward form of the individual are changed, yet his nature is one and the same, his person is one and the same . . . . In like manner, it behoves Christian doctrine to follow the same laws of progress, so as to be consolidated by years, enlarged by time, refined by age, and yet, withal, to continue uncorrupt and unadulterated, complete and perfect in all the measurement of its parts, and, so to speak, in all its proper members and senses, admitting no change, no waste of its distinctive property, no variation in its limits . . . For it is right that those ancient doctrines of heavenly philosophy should, as time goes on, be cared for, smoothed, polished; but not that they should be changed, not that they should be maimed, not that they should be mutilated. They may receive proof, illustration, definiteness; but they must retain withal their completeness, their integrity, their characteristic properties. (Chapter XXIII, 55, 56, 57 [NPNF 2 XII:148])
Material but not Formal Sufficiency of the Bible
Here, possibly, some one may ask, Do heretics also appeal to Scripture? They do indeed, and with a vengeance; for you may see them scamper through every single book of Holy Scriptures . . . (Chapter XXV, 64 [NPNF 2 XII:150])
. . . they must interpret the sacred Canon according to the traditions of the Universal Church and in keeping with the rules of Catholic doctrine, in which Catholic and Universal Church, moreover, they must follow universality, antiquity, consent. (Chapter XXVII, 70 [NPNF 2 XII:152])
We said above that it has always been the custom of Catholics, and still is, to prove the true faith in these two ways; first by the authority of the Divine Canon, and next by the tradition of the Catholic Church. Not that the Canon alone does not of itself suffice for every question, but seeing that the more part, interpreting the divine words according to their own persuasion, take up various erroneous opinions, it is therefore necessary that the interpretation of divine Scripture should be ruled according to the one standard of the Church’s belief, especially in those articles on which the foundations of all Catholic doctrine rest. (Chapter XXIX [NPNF 2 XII:153])
[Someone who wishes to stay clear of heresy] should ascertain whether any decision has been given in ancient time as to the matter in question by the whole priesthood of the Catholic Church, with the authority of a General Council: and, secondly, if some new question should arise on which no such decision has been given, they should then have recourse to the opinions of the holy Fathers, of those at least, who, each in his own time and place, remaining in the unity of communion and of the faith, were accepted as approved masters; and whatsoever these may be found to have held, with one mind and with one consent, this ought to be accounted the true and Catholic doctrine of the Church, without any doubt or scruple. (Chapter XXIX, 77 [NPNF 2 XII:154])