Translated by Ch. Browne and J. Swallow. Cf. An Introduction to the Theological Orations of St Gregory
III. What is this that has happened to me, O friends, and initiates, and fellow-lovers of the truth? I was running to lay hold on God, and thus I went up into the Mount, and drew aside the curtain of the Cloud, and entered away from matter and material things, and as far as I could I withdrew within myself. And then when I looked up, I scarce saw the back parts of God;  although I was sheltered by the Rock, the Word that was made flesh for us. And when I looked a little closer, I saw, not the First and unmingled Nature, known to Itself—to the Trinity, I mean; not That which abideth within the first  veil, and is hidden by the Cherubim; but only that Nature, which at last even reaches to us. And that is, as far as I can learn, the Majesty, or as holy David calls it, the Glory  which is manifested among the creatures, which It has produced and governs. For these are the Back Parts of God, which He leaves behind Him, as tokens of Himself  like the shadows and reflection of the sun in the water, which shew the sun to our weak eyes, because we cannot look at the sun himself, for by his unmixed light he is too strong for our power of perception. In this way then shalt thou discourse of God; even wert thou a Moses and a god to Pharaoh;  even wert thou caught up like Paul to the Third Heaven,  and hadst heard unspeakable words; even wert thou raised above them both, and exalted to Angelic or Archangelic place and dignity. For though a thing be all heavenly, or above heaven, and far higher in nature and nearer to God than we, yet it is farther distant from God, and from the complete comprehension of His Nature, than it is lifted above our complex and lowly and earthward sinking composition.
 Exod. xxxiii. 23.
 This veil of the Mercy Seat, spoken of in Exod. xxvi. 31, signifies in Gregory's sense the denial of contemplation of that Highest Nature.
 Ps. viii. 1.
 The Face of God signifies His Essence and Deity, which were before all worlds: His back parts are Creation and Providence, by which He reveals Himself.
 Exod. iv. 2.
 2 Cor. xii. 2.
Reference address : https://www.elpenor.org/gregory-nazianzen/second-theological.asp?pg=2