St. Basil the Great on the Holy Spirit and the Holy Angels
By the Holy Spirit hearts are lifted up, the weak are held by the hand, and those who are advancing are brought to perfection. Shining upon those who are cleansed from every spot, He makes them spiritual by fellowship with Himself. Just as when a sunbeam falls on bright and transparent bodies, they themselves become brilliant too, and shed forth a fresh brightness from themselves, so souls wherein the Spirit dwells, illuminated by the Spirit, themselves become spiritual, and send forth their grace to others. Hence comes foreknowledge of the future, understanding of Mysteries, apprehension of what is hidden, distribution of good gifts, the heavenly citizenship, a place in the chorus of angels, joy without end, abiding in God. . . .
The Spirit is called on as Lord of life, whereas the angels are summoned as allies of their fellow-slaves and faithful witnesses of the truth. It is customary for the saints to deliver the commandments of God in the presence of witnesses, as also the Apostle himself says to Timothy, "The things which you have heard from me in the presence of many witnesses, entrust to faithful men.” And he calls the angels to witness, for he knows that angels shall be present with the Lord when He shall come in the glory of His Father to judge the world in righteousness. For He says, "Whoever shall confess Me before men, him shall the Son of Man also confess before the angels of God, but he that denies Me before men shall be denied before the angels of God.” And Paul in another place says, "When the Lord Jesus shall be revealed from heaven with His angels." Thus he already testifies before the angels, preparing good proofs for himself at the great tribunal.
And not only Paul, but generally all those to whom the Ministry of the Word is committed never cease from testifying, but call heaven and earth to witness, for now every deed that is done is done within them, and in the examination of all the actions of life they will be present with the judged. . . . So the Apostle, likewise, knowing the angels to be set over men as tutors and guardians, calls them to witness. . . . But the Holy Spirit is ranked together with God the Father and the Son, not on account of the emergency of the moment, but on account of the natural fellowship. . . .
Moreover, from the things created at the beginning may be learned the fellowship of the Spirit with the Father and the Son. The pure, intelligent, and supermundane powers are holy, because they have their holiness by the grace of the Holy Spirit. . . . Accordingly, as you are able from the things that are seen to form an analogy of the unseen, glorify the Maker by whom all things were made, visible and invisible, principalities and powers, authorities, thrones, and dominions, and all other reasonable natures whom we cannot name. And in considering the creation, think first of the original cause of all things that are made, the Father; of the creative cause, the Son; of the perfecting cause, the Spirit; so that the ministering spirits subsist by the will of the Father, are brought into being by the operation of the Son, and are perfected by the presence of the Spirit. Moreover, the perfection of the angels by the Holy Spirit is their sanctification and their perseverance in holiness. . . .
You are therefore to perceive three, the Lord who gives the order, the Word who creates, and the Spirit who confirms. And what could such confirmation be other than the perfecting of holiness? This sanctification is the confirmation of firmness, unchangeableness, and fixity in good. But there is no sanctification without the Holy Spirit. The powers of the heavens are not holy by nature; otherwise there would in this respect be no difference between them and the Holy Spirit. It is in proportion to their relative excellence that they have their measure of holiness from the Spirit. The branding-iron is conceived of together with the fire; and yet the material and the fire are distinct. So too in the case of the heavenly powers; their substance is an aerial spirit, or an immaterial fire, as it is written, "Who makes His angels spirits and His ministers a flame of fire;" wherefore they exist in space and become visible, and appear in their proper bodily form to those who are worthy. But their sanctification, being external to their substance, superinduces their perfection through the communion of the Holy Spirit. They keep their rank by their abiding in the good and true, and while they retain their freedom of will, never fall away from their patient attendance on Him who is truly good.
Consequently, if you do away with the Spirit, the hosts of the angels are disbanded, the dominions of archangels are destroyed, all is thrown into confusion, and their life loses law, order, and distinctness. For how are angels to cry "Glory to God in the highest" without being empowered by the Spirit? For "No man can say that Jesus is the Lord but by the Holy Spirit; and no man speaking by the Spirit of God calls Jesus accursed" — as might be said by wicked and hostile spirits, whose fall establishes our statement of the freedom of the will of the invisible powers. As such beings are created in a condition of equipoise between virtue and vice, they also need the succor of the Spirit.
I indeed maintain that even Gabriel in no other way foretells events to come than by the foreknowledge of the Spirit, by reason of the fact that one of the boons distributed by the Spirit is prophecy. And whence did he who was ordained to announce the Mysteries of the vision to the Prophet Daniel derive the wisdom whereby he was enabled to teach hidden things, if not from the Holy Spirit? The revelation of Mysteries is indeed the peculiar function of the Spirit, as it is written, "God has revealed them unto us by His Spirit." And how could "thrones, dominions, principalities and powers" live their blessed life, if they did not "behold the Face of the Father which is in heaven"? But to behold His Face is impossible without the Spirit. Just as at night, if you withdraw the light from the house, the eyes fall blind and their faculties become inactive, and the worth of objects cannot be discerned, and gold is trodden on in ignorance as though it were iron, so in the order of the intellectual world it is impossible for the high life of Law to abide without the Spirit. For it to function in that way is no more possible than for an army to maintain its discipline in the absence of its commander, or a chorus its harmony without the guidance of its director.
How could the Seraphim cry "Holy, Holy, Holy," were they not taught by the Spirit how often true religion requires them to lift their voice in this ascription of glory? Do "all His angels" and "all His hosts" praise God? It is through the co-operation of the Spirit. Do a "thousand thousand" angels stand before Him, and "ten thousand times ten thousand" ministering spirits? They are blamelessly doing their proper work by the power of the Spirit. All the glorious and unspeakable harmony of the highest heavens, in the service of God and the mutual concord of the celestial powers, can only be preserved by the direction of the Spirit. Thus with those beings who are not gradually perfected by increase and advance, but are perfect from the moment of the creation, there is in creation the presence of the Holy Spirit, who confers on them the grace that flows from Him for the completion and perfection of their essence.
(Excerpts from St. Basil’s treatise On the Holy Spirit, tr. by Philip Schaff, modestly updated)