Pope St. Simplicius, “Quantum presbyterorum” to Acacius, Bishop of Constantinople, January 9, 476 A.D.: “Because, according to the extant doctrine of our predecessors of sacred memory, against which it is wrong to argue, whoever seems to understand rightly, does not desire to be taught by new assertions, but all [matters] in which either he who has been deceived by heretics can be instructed, or he who is about to be planted in the vineyard of the Lord can be trained, are clear and perfect;” (Denz. 159)