God may be known exactly and precisely, declared Eunomius: he is unbegotten substance. This knowledge is available through philosophical reflection to all alike. To understand the meaning of the word “unbegotten” in its divine reference is to comprehend the divine being. It is to know God definitively, completely; it is to know God as he knows himself; it is to know what God is.
The divine ineffability had long been a staple of Christian teaching. In the third century Origen wrote, “God is incomprehensible and incapable of being measured.” “To scrutinize the nature of God,” St Cyril of Jerusalem averred, “is impossible.” Even the heretic Arius accepted the principle that God is beyond comprehension and even went so far as to assert that God is incomprehensible to the Son: “God is inexpressible to the Son. For He is in himself what He is, that is, indescribable” (Thalia). Hence it is not surprising that the innovative claim to comprehend the Deity scandalized orthodox theologians. In the early 360s St Basil of Caesarea composed the first substantive response to Eunomius, his Contra Eunomium: “There is no one name,” he insisted, “sufficiently broad to take in the whole nature of God” (1.10). “I reckon that the comprehension of God’s essence is beyond not just men alone but beyond every rational nature. When I say rational, I mean created. For the Father is known by the Son alone, and by the Holy Spirit” (1.14).
But the views of Eunomius continued to spread. In 380 St Gregory of Nazianzus devoted his Second Theological Oration to the refutation of the thesis of divine comprehensibility.
Before tackling Oration 28 readers might find it helpful to read the following chapters in the Old Testament: Exodus 19, 24-26, 33-34; Isaiah 6; and Ezekiel 1-3. St Gregory does not ground his theology of God upon philosophy and speculation. The theophanies of the Old Testament are critical for him. We know God only through his self-revelation. Gregory refuses to meet the Eunomians on their own rationalistic terms. His goal is to present a vision of the God of Jesus Christ, in all of his mystery and ineffability. As he states midway through his homily, the plain point of his discourse is to expound on “the incomprehensibility of deity to the human mind and its totally unimaginable grandeur” (28.11).
As he did in preceding orations and will do again in later ones, Gregory invites his audience to ascend the holy mountain. The story of Moses’ encounter with the Holy One of Israel on Mount Sinai is decisive for the Theologian’s understanding of God:
Moses said, “Please show me your glory.” And he said, “I will make all my goodness pass before you and will proclaim before you my name ‘The Lord.’ And I will be gracious to whom I will be gracious, and will show mercy on whom I will show mercy. But,” he said, “you cannot see my face, for man shall not see me and live.” And the Lord said, “Behold, there is a place by me where you shall stand on the rock, and while my glory passes by I will put you in a cleft of the rock, and I will cover you with my hand until I have passed by. Then I will take away my hand, and you shall see my back, but my face shall not be seen.” And he rose early in the morning and went up on Mount Sinai, as the Lord had commanded him, and took in his hand two tablets of stone. The Lord descended in the cloud and stood with him there, and proclaimed the name of the Lord. The Lord passed before him and proclaimed, “The Lord, the Lord, a God merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness, keeping steadfast love for thousands, forgiving iniquity and transgression and sin, but who will by no means clear the guilty, visiting the iniquity of the fathers on the children and the children’s children, to the third and the fourth generation.” (Ex 33:18-23; 34:4-7)
Hidden in the cleft of the rock, Moses sees the hind parts of the Lord as he passes by; but God does not allow him to see the his face—”for man shall not see me and live.”
St Gregory shares with his audience his own contemplative experience of divinity, as interpreted through the Mosaic theophany:
What happened to me, friends and initiates and fellow lovers of the truth? I was running to comprehend God, and so I went up into the mountain and came through the cloud and entered away from matter and material things, and as far as I could I withdrew within myself. Then when I looked up, I barely saw the back parts of God; and in this I was sheltered by the rock, the Word that was made flesh for us. When I looked a little closer I saw, not the first and pure nature, which is known to itself—to the Trinity, I mean—and that part of it that abides within the first veil and is hidden by the cherubim; but only that part of it that is posterior and comes down to us. This is, as far as I know, God’s majesty that is manifested among the creatures that he has produced and governs—or as holy David calls it, God’s “glory.” For these are the back parts of God, which he leaves behind as tokens of himself, like the shady reflections of the sun in the water, which show the sun to our weak eyes because we cannot look at the sun itself; for by its unmixed light it defeats our perception. In this way, then, you shall do theology, even if you are a Moses and “a god to Pharaoh,” even if you are caught up like Paul “to the third heaven” and heard “unspeakable words,” even if you are raised above them both and exalted to angelic or archangelic status and rank! For even if something is all heavenly—or even above heaven, much higher in nature than we are, and nearer to God—it is still farther from God and from the complete comprehension of him, than it rises above our complex and lowly and earthward-sinking composition. (28.3; translated by Christopher Beeley, Gregory of Nazianzus on the Trinity and the Knowledge of God, pp. 90-91)
“I was running to comprehend God,” declares Gregory; that is to say, as the last line in the quoted passage makes clear, he was seeking to attain “complete comprehension” of God, just as Eunomius believed he had achieved. But Gregory fails in his quest. His story is a story of defeat (Beeley, p. 93). Gregory ran up the mountain to fully comprehend the essence of God; but all he could see, all he was permitted to see, was the divine glory. Despite years of study, purification, and ascetical preparation, the prime nature remains hidden behind the wings of the cherubim. To us is given only the backside of the Lord.
Gregory is well aware of his own frailty (28.2), but lest anyone suggest that his experience is atypical, he cites numerous examples from the Scriptures (28.18-20). None of the biblical saints ever saw the face of the living God; none ever claimed to offer a definition of the divine nature—not Enoch, who was taken up into paradise without experiencing death; not Abraham, who was justified by faith and “saw God but not as God”; not Jacob, who dreamt of the ladder of heaven, with angels ascending and descending, and who wrestled with the mysterious visitor by the river Jabbok; not Elijah, who encountered the Creator in a soft breeze; not Isaiah, who saw the Lord surrounded by the cherubim; not Peter, “who was more fervent than the rest for knowledge of Christ”; not Paul, who was caught up into the third heaven. “None of these I talk of,” explains the Nazianzen, “nor any other of their sort, stood within the essential ‘basis,’ as Scripture has it, ‘of the Lord.’ None saw, none told, of God’s nature” (28.19).