“The following, then, are the mysteries which we have learned from the holy oracles, as the divine Dionysius the Areopagite said: that God is the cause and beginning of all: the essence of all that have essence: the life of the living: the reason of all rational beings: the intellect of all intelligent beings: the recalling and restoring of those who fall away from Him: the renovation and transformation of those that corrupt that which is natural: the holy foundation of those who are tossed in unholiness: the steadfastness of those who have stood firm: the way of those whose course is directed to Him and the hand stretched forth to guide them upwards. And I shall add He is also the Father of all His creatures (for God, Who brought us into being out of nothing, is in a stricter sense our Father than are our parents who have derived both being and begetting from Him): the shepherd of those who follow and are tended by Him: the radiance of those who are enlightened: the initiation of the initiated: the deification of the deified: the peace of those at discord: the simplicity of those who love simplicity: the unity of those who worship unity: of all beginning the beginning, super-essential because above all beginnings: and the good revelation of what is hidden, that is, of the knowledge of Him so far as that is lawful for and attainable by each. Deity being incomprehensible is also assuredly nameless. Therefore since we know not His essence, let us not seek for a name for His essence. For names are explanations of actual things. But God, Who is good and brought us out of nothing into being that we might share in His goodness, and Who gave us the faculty of knowledge, not only did not impart to us His essence, but did not even grant us the knowledge of His essence. For it is impossible for nature to understand fully the supernatural. Moreover, if knowledge is of things that are, how can there be knowledge of the super-essential? Through His unspeakable goodness, then, it pleased Him to be called by names that we could understand, that we might not be altogether cut off from the knowledge of Him but should have some notion of Him, however vague. Inasmuch, then, as He is incomprehensible, He is also unnamable. But inasmuch as He is the cause of all and contains in Himself the reasons and causes of all that is, He receives names drawn from all that is, even from opposites: for example, He is called light and darkness, water and fire: in order that we may know that these are not of His essence but that He is super-essential and unnamable: but inasmuch as He is the cause of all, He receives names from all His effects.
Wherefore, of the divine names, some have a negative signification, and indicate that He is super-essential: such are “non-essential,” “timeless,” “without beginning,” “invisible”: not that God is inferior to anything or lacking in anything (for all things are His and have become from Him and through Him and endure in Him), but that He is pre-eminently separated from all that is. For He is not one of the things that are, but over all things. Some again have an affirmative signification, as indicating that He is the cause of all things. For as the cause of all that is and of all essence, He is called both Ens [sic???] and Essence. And as the cause of all reason and wisdom, of the rational and the wise, He is called both reason and rational, and wisdom and wise. Similarly He is spoken of as Intellect and Intellectual, Life and Living, Power and Powerful, and so on with all the rest. Or rather those names are most appropriate to Him which are derived from what is most precious and most akin to Himself. That which is immaterial is more precious and more akin to Himself than that which is material, and the pure than the impure, and the holy than the unholy: for they have greater part in Him. So then, sun and light will be more apt names for Him than darkness, and day than night, and life than death, and fire and spirit and water, as having life, than earth, and above all, goodness than wickedness: which is just to say, being more than not being. For goodness is existence and the cause of existence, but wickedness is the negation of goodness, that is, of existence. These, then, are the affirmations and the negations, but the sweetest names are a combination of both: for example, the super-essential essence, the Godhead that is more than God, the beginning that is above beginning and such like. Further there are some affirmations about God which have in a pre-eminent degree the force of denial: forexample, darkness: for this does not imply that God is darkness but that He is not light, but above light.
God then is called Mind and Reason and Spirit and Wisdom and Power, as the cause of these, and as immaterial, and maker of all, and omnipotent. And these names are common to the whole Godhead, whether affirmative or negative. And they are also used of each of the subsistences [hypostases/persons] of the Holy Trinity in the very same and identical way and with their full significance. For when I think of one of the subsistences, I recognize it to be perfect God and perfect essence: but when I combine and reckon the three together, I know one perfect God. For the Godhead is not compound but in three perfect subsistences, one perfect indivisible and uncompound God. And when I think of the relation of the three subsistences to each other, I perceive that the Father is super-essential Sun, source of goodness, fathomless sea of essence, reason, wisdom, power, light, divinity: the generating and productive source of good hidden in it. He Himself then is mind, the depth of reason, begetter of the Word, and through the Word the Producer of the revealing Spirit. And to put it shortly, the Father has no reason, wisdom, power, will, save the Son Who is the only power of the Father the immediate cause of the creation of the universe: as perfect subsistence begotten of perfect subsistence in a manner known to Himself, Who is and is named the Son. And the Holy Spirit is the power of the Father revealing the hidden mysteries of His Divinity, proceeding from the Father through the Son in a manner known to Himself, but different from that of generation. Wherefore the Holy Spirit is the perfecter of the creation of the universe. All the terms, then, that are appropriate to the Father, as cause, source, begetter, are to be ascribed to the Father alone: while those that are appropriate to the caused, begotten Son, Word, immediate power, will, wisdom, are to be ascribed to the Son: and those that are appropriate to the caused, processional, manifesting, perfecting power, are to be ascribed to the Holy Spirit. The Father is the source and cause of the Son and the Holy Spirit: Father of the Son alone and producer of the Holy Spirit. The Son is Son, Word, Wisdom, Power, Image, Effulgence, Impress of the Father and derived from the Father. But the Holy Spirit is not the Son of the Father but the Spirit of the Father as proceeding from the Father. For there is no impulse without Spirit. And we speak also of the Spirit of the Son, not as through proceeding from Him, but as proceeding through Him from the Father. For the Father alone is cause.”
St John of Damascus “Further and more accurately concerning Divine Names”, Book 1, Chapter 12: An Exact Exposition of the Orthodox Faith from Post-Nicene Fathers