Translated by Ch. Browne and J. Swallow.
VIII. And when Infinity is considered from two points of view, beginning and end (for that which is beyond these and not limited by them is Infinity), when the mind looks to the depth above, not having where to stand, and leans upon phenomena to form an idea of God, it calls the Infinite and Unapproachable which it finds there by the name of Unoriginate. And when it looks into the depths below, and at the future, it calls Him Undying and Imperishable. And when it draws a conclusion from the whole it calls Him Eternal (aionios). For Eternity (haion) is neither time nor part of time; for it cannot be measured. But what time, measured by the course of the sun, is to us, that Eternity is to the Everlasting, namely, a sort of time-like movement and interval co-extensive with their existence. This, however, is all I must now say about God; for the present is not a suitable time, as my present subject is not the doctrine of God, but that of the Incarnation. But when I say God, I mean Father, Son, and Holy Ghost. For Godhead is neither diffused beyond these, so as to bring in a mob of gods; nor yet is it bounded by a smaller compass than these, so as to condemn us for a poverty-stricken conception of Deity; either Judaizing to save the Monarchia, or falling into heathenism by the multitude of our gods. For the evil on either side is the same, though found in contrary directions. This then is the Holy of Holies,  which is hidden even from the Seraphim, and is glorified with a thrice repeated Holy,  meeting in one ascription of the Title Lord and God, as one of our predecessors has most beautifully and loftily pointed out.
IX. But since this movement of self-contemplation alone could not satisfy Goodness, but Good must be poured out and go forth beyond Itself to multiply the objects of Its beneficence, for this was essential to the highest Goodness, He first conceived the Heavenly and Angelic Powers. And this conception was a work fulfilled by His Word, and perfected by His Spirit. And so the secondary Splendours came into being, as the Ministers of the Primary Splendour; whether we are to conceive of them as intelligent Spirits, or as Fire of an immaterial and incorruptible kind, or as some other nature approaching this as near as may be. I should like to say that they were incapable of movement in the direction of evil, and susceptible only of the movement of good, as being about God, and illumined with the first rays from God—for earthly beings have but the second illumination; but I am obliged to stop short of saying that, and to conceive and speak of them only as difficult to move because of him,  who for his splendour was called Lucifer, but became and is called Darkness through his pride; and the apostate hosts who are subject to him, creators of evil  by their revolt against good and our inciters.
 The Holy of Holies here means the Holy Trinity.
 The reference is to the Ter Sanctus or Triumphal Hymn, which is found in every Liturgy. The previous writer referred to is thought by some to be S. Athanasius, but by others S. Dionysius the Areopagite, who has some words on this point in his treatise De Coelest. Hier., c. 7. But the most competent scholars deny the authenticity of the works attributed to S. Dionysius, and place them from one hundred to one hundred and fifty years later than S. Gregory's time.
 S. Thomas Aquinas (Summa I., qu. 63, art. 7) gives reasons for thinking that Satan was originally the highest of all the angelic hosts. This, however, is an opinion in which many high authorities differ from him. At any rate, Satan as Lucifer must have held a very high place.
 Evil, says Nicetas here, has no positive existence, but is the negation of good. "The faculties of mind and body which are used in a sinful action are indeed things, and are the creatures of God; but the sin itself is not a thing, and consequently not a creature. God is indeed the Author of all that is, of every substance; but sin is not a substance, and is not. It is a declination from substance and from being, and not a part of it." (Mozley, Treatise on the Augustinian doctrine of predestination.)
Reference address : https://www.elpenor.org/gregory-nazianzen/birthday-christ.asp?pg=5