Gregory of Nazianzus : [Where] do you get those fortresses of yours, "ingenerate" and "unoriginate," from—or where the term "immortal"? Show us the express words, or we cross them out as unscriptural, and you will be dead as a result of your own principles, since the words, the wall of defense you trusted in, will have been destroyed. Is it not plain that these terms derived from passages that imply, without actually mentioning them? Which passages? What about "I am the first, and I am hereafter," and "Before me there is no other God and after me there shall be none," "for everything that exists" [God is saying] "is mine, without beginning or ending"? You have taken the truths that there is nothing before God and that he has no prior case, and you have given him the titles "unoriginate" and "ingenerate." The fact that there is no halt to his ongoing existence means he is "immortal" and "indestructible." — ON THE HOLY SPIRIT, THEOLOGICAL ORATION 5(31).23 Gregory of Nyssa : The great Isaiah thus speaks of the Divine nature with reference to these doctrines, in his exalted utterance,—who speaks in the person of the Deity, "I am the first, and hereafter am I, and no God was before Me, and no God shall be after Me." … Since, then, neither is that God which was before God, nor is that God which is after God, (for that which is after God is the creation, and that which is anterior to God is nothing, and Nothing is not God;—or one should rather say, that which is anterior to God is God in His eternal blessedness, defined in contradistinction to Nothing;)—since, I say, this inspired utterance was spoken by the mouth of the prophet, we learn by his means the doctrine that the Divine Nature is one, continuous with Itself and indiscerptible, not admitting in Itself priority and posteriority, though it be declared in Trinity. Since, then, the saying is the saying of God, whether you grant that the words are the words of the Father or of the Son, the orthodox doctrine is equally upheld by either. For if it is the Father that speaks thus, He bears witness to the Son that He is not "after" Himself: for if the Son is God, and whatever is "after" the Father is not God, it is clear that the saying bears witness to the truth that the Son is in the Father, and not after the Father. If, on the other hand, one were to grant that this utterance is of the Son, the phrase, "None hath been before Me," will be a clear intimation that He Whom we contemplate "in the Beginning" is apprehended together with the eternity of the Beginning. — AGAINST EUNOMIUS 5:1 Theodoret of Cyrus : From the beginning, [Isaiah] says, God has made announcements concerning righteousness. He made the covenant with Abraham in these terms: "All the nations of the earth shall be blessed in your seed," and he [renewed] the covenant with Isaac, Jacob, Moses and David. This is what he has likewise announced through other prophets. "I, God, I AM the first, and I AM the future." The One who gave the Old Testament, he says, is not different from the One who established the New. The divine nature is one, always the same and unchanging. — COMMENTARY ON Isaiah 12:41.4