John Cassian, who had a profound impact on monasticism thanks to his influence on Benedict, comments on the universality of the orthodox consensus:
“The consensus of all ought of itself to be enough to refute heresy; for the authority of all shows indubitable truth, and a perfect reason results where no one disputes it. Therefore if a [person] seeks to hold opinions contrary to these, we should, at the very outset, condemn his perversity rather than listen to his assertions. For someone who impugns the judgment of all announces his [or her] own condemnation beforehand, and a [person] who disturbs what had been determined by all is not even given a hearing. For when the truth has been established by all [people] once and for all, whatever arises contrary to it is by this very fact to be recognized at once as a falsehood, because it differs from the truth.”
Cassian’s insight is similar to what would later be called the Vincentian Canon, named after its progenitor St. Vincent of Lerins. He argued, “we take the greatest care to hold that which has been believed everywhere, always and by all.”
The early church, led by the apostles and their successors, saw themselves as in continuity with the teaching of Jesus handed on by the disciples. They determined to hold “the authority of all,” led by the Holy Spirit, above any individual or regional variations.
In an age where atheist preachers are fighting to keep their pulpits, this insight is more important than ever. The Christian movement is not subject to my personal whims but is, in Jude’s language, the “faith once delivered,” and the health of the Body is not possible unless we hold fast to that deposit of faith and practice held authoritative everywhere, by everyone, and for all time.
Source: Pelikan, The Christian Tradition: Volume 1, 338-339.