St. Athanasius the Great ca. 297-373
For, what our Fathers have delivered, this is truly doctrine; and this is truly the token of doctors, to confess the same thing with each other, and to vary neither from themselves nor from their fathers; whereas they who have not this character are to be called not true doctors but evil. Thus the Greeks, as not witnessing to the same doctrines, but quarrelling one with another, have no truth of teaching; but the holy and veritable heralds of the truth agree together, and do not differ. For though they lived in different times, yet they one and all tend the same way, being prophets of the one God, and preaching the same Word harmoniously. (De Decretis 2.4)
Such are the machinations of these men against the truth: but their designs are manifest to all the world, though they attempt in ten thousand ways, like eels, to elude the grasp, and to escape detection as enemies of Christ. Wherefore I beseech you, let no one among you be deceived, no one seduced by them; rather, considering that a sort of judaical impiety is invading the Christian faith, be ye all zealous for the Lord; hold fast, every one, the faith we have received from the Fathers, which they who assembled at Nicæa recorded in writing, and endure not those who endeavour to innovate thereon. And however they may write phrases out of the Scripture, endure not their writings; however they may speak the language of the Orthodox, yet attend not to what they say; for they speak not with an upright mind, but putting on such language like sheeps’ clothing, in their hearts they think with Arius, after the manner of the devil, who is the author of all heresies. For he too made use of the words of Scripture, but was put to silence by our Saviour. (Ad Episcopus Aegypti et Libyae 8)