My fellow BB member and Anglican, Doubting Thomas, has also commented on Vincent and, IIRC, has said this, and I would thoroughly endorse and echo his words:
So after stating his belief in the (material) sufficiency of Scripture, Vincent argues that the Church's standard interpretive Tradition is necessary because of the various ways in which different people (particularly heretics) have misinterpreted the Scriptures. To make this especially relevant to the situation today, and why the consensus of Tradition is necessary, one can substitute modern-day denominations and see how his argument still holds:
"For this reason,—because, owing to the depth of Holy Scripture, all do not accept it in one and the same sense, but one understands its words in one way, another in another; so that it seems to be capable of as many interpretations as there are interpreters. For Luther expounds it one way, Calvin another, Zwingli another, Methodists, Baptists, Mennonites, another, Adventists, Pentecostals, Presbyterians, Unitarians, Quakers, Campbellites, Plymouth Brethren, another, lastly, Jehovah Witnesses another. Therefore, it is very necessary, on account of so great intricacies of such various error, that the rule for the right understanding of the prophets and apostles should be framed in accordance with the standard of Ecclesiastical and Catholic interpretation."
Vincent concludes by laying down the criteria for interpretation:
"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 consentient definitions and determinations of all, or at the least of almost all priests and doctors.
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.
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."
That there are folks who have mutually contradictory interpretations--on what the Scriptures seem to teach on such vital issues as the nature of God and the nature of Christ--should not be surprising. The Apostle Peter warned in his Second Epistle that there were already those who were "twisting Scripture" to "their own destruction". The question is how do we know: (1) who are the ones "rightly dividing the word of truth", and (2) who are the ones "twisting Scripture to their own destruction"? For each group, as I have said on the first page, is convinced that they are practising the former, while those who disagree are potentially practising the latter. Who decides between them, and/or how does one know who is right?
I submit the answer to the "how" question lies in the Apostolic Tradition. This is mentioned by Paul, particularly to the church of the Thessalonians:
"Therefore, brethren, stand fast and hold the traditions you were taught whether by word or our epistle." (2 Thess 2:15)
Notice that Paul doesn't elevate one mode of receiving the Tradition--his oral word or his written epistle--above the other; the authority is the same. Though we can't be sure that the content is exactly the same in every single detail of the oral and written forms, we can surmise that they testify to the same material Truth and therefore don't contradict one another. From another one of Paul's letters, this time to Timothy, it seems that this oral Tradition at the very least refers to (and consists of) the specific body of teaching and doctrine that was handed down by the Apostles:
"Hold fast the sound pattern of words which you have heard from me." (2 Tim 1:13)
So, there was a "sound pattern" of oral teaching recognizable to Timothy (and presumably to the others taught by the Apostles) which was to be kept and by which the early Christians could recognize truth from error. By this "sound pattern" the early Christians could therefore "rightly divide" the word of truth. On the other hand those who did not hold fast the "sound pattern of words" received orally from the Apostles could be considered "untaught and unstable" (2 Peter 3:16) and were liable to misinterpret the Apostle's writings (and the other Scriptures) and thus to "twist the Scriptures to their own destruction".
What's more is that Paul expects Timothy to be able to transmit orally that which he received from Paul: "And the things you have heard from me among many witnesses, commit these to faithful men who will be able to teach others also." (2 Tim 2:2). Notice here that the "things" Timothy received were not exclusive or private but were heard "among many witnesses", and how the faithful men to whom Timothy committed these "things" were to teach others as well (that's four generations of oral transmission). The public reception of the Tradition in the community could thus serve as a "check" or "balance" on those who would deviate from the "sound pattern" while claiming (ie like the Gnostics did) to be handing down some new teaching allegedly received "secretly" from the Apostles.
As for the answer of "who decides?", it is obviously the CHURCH corporately. As Paul wrote to Timothy, the CHURCH is "the pillar and ground of truth". (1 Timothy 3:15). Christ commissioned His Apostles, the collective foundation of the Church (Eph 2:20), by breathing His Spirit, the Spirit of Truth (John 16:13), on them (John 20:22). The Apostles by the Spirit preached the Truth and established local congregations of the Church to whom they delivered the faith once for all (Jude 3) in "sound patterns of words" (2 Tim 1:13). Some of the Apostles by the Spirit also wrote inspired authoritative epistles and narratives to some of these same congregations. The Church in time, led by the Spirit, could finally come to a consensus on the limits of the Scriptural Canon--by determining which works conformed to the Tradition received ("sound pattern"), and those which, though claiming apostolic authorship, did not (ie Gnostic and Ebionite texts)
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