Exact Exposition of the Orthodox Faith (book II, chapter 3, “Concerning angels”) by Saint John of Damascus:
He is Himself the Maker and Creator of the angels: for He brought them out of nothing into being and created them after His own image, an incorporeal race, a sort of spirit or immaterial fire: in the words of the divine David, He maketh His angels spirits, and His ministers a flame of fire: and He has described their lightness and the ardour, and heat, and keenness and sharpness with which they hunger for God and serve Him, and how they are borne to the regions above and are quite delivered from all material thought.
An angel, then, is an intelligent essence, in perpetual motion, with free-will, incorporeal, ministering to God, having obtained by grace an immortal nature: and the Creator alone knows the form and limitation of its essence. But all that we can understand is, that it is incorporeal and immaterial. For all that is compared with God Who alone is incomparable, we find to be dense and material. For in reality only the Deity is immaterial and incorporeal.
The angel’s nature then is rational, and intelligent, and endowed with free-will, changeable in will, or fickle. For all that is created is changeable, and only that which is un-created is unchangeable. Also all that is rational is endowed with free-will. As it is, then, rational and intelligent, it is endowed with free-will: and as it is created, it is changeable, having power either to abide or progress in goodness, or to turn towards evil.
It is not susceptible of repentance because it is incorporeal. For it is owing to the weakness of his body that man comes to have repentance.
It is immortal, not by natures but by grace. For all that has had beginning comes also to its natural end. But God alone is eternal, or rather, He is above the Eternal: for He, the Creator of times, is not under the dominion of time, but above time.
They are secondary intelligent lights derived from that first light which is without beginning, for they have the power of illumination; they have no need of tongue or hearing, but without uttering words they communicate to each other their own thoughts and counsels.
Through the Word, therefore, all the angels were created, and through the sanctification by the Holy Spirit were they brought to perfection, sharing each in proportion to his worth and rank in brightness and grace.
They are circumscribed: for when they are in the Heaven they are not on the earth: and when they are sent by God down to the earth they do not remain in the Heaven. They are not hemmed in by walls and doors, and bars and seals, for they are quite unlimited. Unlimited, I repeat, for it is not as they really are that they reveal themselves to the worthy men to whom God wishes them to appear, but in a changed form which the beholders are capable of seeing. For that alone is naturally and strictly unlimited which is un-created. For every created thing is limited by God Who created it.
Further, apart from their essence they receive the sanctification from the Spirit: through the divine grace they prophesy: they have no need of marriage for they are immortal.
Seeing that they are minds they are in mental places, and are not circumscribed after the fashion of a body. For they have not a bodily form by nature, nor are they tended in three dimensions. But to whatever post they may be assigned, there they are present after the manner of a mind and energise, and cannot be present and energise in various places at the same time.
Whether they are equals in essence or differ from one another we know not. God, their Creator, Who knoweth all things, alone knoweth. But they differ from each other in brightness and position, whether it is that their position is dependent on their brightness, or their brightness on their position: and they impart brightness to one another, because they excel one another in rank and nature. And clearly the higher share their brightness and knowledge with the lower.
They are mighty and prompt to fulfil the will of the Deity, and their nature is endowed with such celerity that wherever the Divine glance bids them there they are straightway found. They are the guardians of the divisions of the earth: they are set over nations and regions, allotted to them by their Creator: they govern all our affairs and bring us succour. And the reason surely is because they are set over us by the divine will and command and are ever in the vicinity of God.
With difficulty they are moved to evil, yet they are not absolutely immoveable: but now they are altogether immoveable, not by nature but by grace and by their nearness to the Only Good.
They behold God according to their capacity, and this is their food.
They are above us for they are incorporeal, and are free of all bodily passion, yet are not passionless: for the Deity alone is passionless.
They take different forms at the bidding of their Master, God, and thus reveal themselves to men and unveil the divine mysteries to them.
They have Heaven for their dwelling-place, and have one duty, to sing God’s praise and carry out His divine will.
Moreover, as that most holy, and sacred, and gifted theologian, Dionysius the Areopagite says, All theology, that is to say, the holy Scripture, has nine different names for the heavenly essences. These essences that divine master in sacred things divides into three groups, each containing three. And the first group, he says, consists of those who are in God’s presence and are said to be directly and immediately one with Him, viz., the Seraphim with their six wings, the many-eyed Cherubim and those that sit in the holiest thrones. The second group is that of the Dominions, and the Powers, and the Authorities; and the third, and last, is that of the Rulers and Archangels and Angels
Some, indeed, like Gregory the Theologian, say that these were before the creation of other things. He thinks that the angelic and heavenly powers were first and that thought was their function. Others, again, hold that they were created after the first heaven was made. But all are agreed that it was before the foundation of man. For myself, I am in harmony with the theologian. For it was fitting that the mental essence should be the first created, and then that which can be perceived, and finally man himself, in whose being both parts are united.
But those who say that the angels are creators of any kind of essence whatever are the mouth of their father, the devil. For since they are created things they are not creators. But He Who creates and provides for and maintains all things is God, Who alone is uncreate and is praised and glorified in the Father, the Son, and the Holy Spirit.