Another great text from Gregory of Nazianzus. This from his Second Letter to Cledonius, in Christology of the Later Fathers, pp. 228f:
O monstrous absurdity! They proclaim to us to-day a wisdom hidden ever since the time of Christ — a thing worthy of our tears. For if the faith began thirty years ago, when nearly four hundred years had passed since Christ was manifested, vain all that time will have been our Gospel, and vain our faith; in vain will the Martyrs have borne their witness, and in vain have so many and so great Prelates presided over the people; and Grace is a matter of metres and not of the faith…. Now, if anyone thinks that we write all this willingly and not upon compulsion, and that we are dissuading from unity, and not doing our utmost to promote it, let him know that he is very much mistaken, and has not made at all a good guess at our desires, for nothing is or ever has been more valuable in our eyes than peace, as the facts themselves prove; though their actions and brawlings against us altogether exclude unanimity.