We said, further, that in this same ecclesiastical antiquity two points are very carefully and earnestly to be held in view by those who would keep clear of heresy: first, they should ascertain whether any decision has been given in ancient times 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.
Vincent of Lérins, “The Commonitory of Vincent of Lérins,” in Sulpitius Severus, Vincent of Lérins, John Cassian, ed. Philip Schaff and Henry Wace, trans. C. A. Heurtley, vol. 11, A Select Library of the Nicene and Post-Nicene Fathers of the Christian Church, Second Series (New York: Christian Literature Company, 1894), 153–154.