In his denial of the deity of Christ, Arius was arguably the most notorious heretic of the early church.
Though Arius’s heretical views were soundly condemned by the Council of Nicaea (in A.D. 325), the controversy he sparked raged for another fifty years throughout the Roman Empire. During those tumultuous decades, the defenders of Trinitarian orthodoxy often found themselves outnumbered and out of favor with the imperial court. Yet they refused to compromise.
Among them, most famously, stood Athanasius of Alexandria—exiled on five different occasions for his unwavering commitment to the truth. He was joined by the Cappadocian Fathers: Basil of Caesarea, Gregory of Nazianzas, and Gregory of Nyssa.
But how did these early Christian leaders know that the doctrine they were defending was, in fact, a truth worth fighting for? How did they know they were right and the Arians were wrong? Was it on the basis of oral tradition, a previous church council, or an edict from the bishop of Rome?
No. They ultimately defended the truth by appealing to the Scriptures.
Gregory of Nyssa makes that point explicit in a letter to Eustathius. The Arians claimed that their tradition (or “custom”) did not allow for the Trinitarian position. Gregory responded with the following:
What then is our reply? We do not think that it is right to make their prevailing custom the law and rule of sound doctrine. For if custom is to avail for proof of soundness, we too, surely, may advance our prevailing custom; and if they reject this, we are surely not bound to follow theirs. Let the inspired Scripture, then, be our umpire, and the vote of truth will surely be given to those whose dogmas are found to agree with the Divine words. (Dogmatic Treatises, Book 12. On the Trinity, To Eustathius.)
When Arian custom ran contrary to Trinitarian custom, to what authority did Gregory appeal? The Scriptures.
As Gregory rightly understood, Scripture is a higher authority than tradition. That is why he appealed to the Word of God as the final arbiter in the debate over Arianism.
In so doing, Gregory provides a vivid illustration of the principle of sola Scriptura, twelve centuries before the Reformation. Of course, Gregory was not the only church father who shared in that conviction.
Though many others could be cited, here is a small sampling from eight church fathers who shared Gregory’s perspective on the authority of Scripture.