If, then, they declare the Holy Ghost to be blended of both, they must consequently view that blending as of a prior with a posterior thing; and, according to them, He will be prior to Himself; and reversely, posterior to Himself; from the Uncreated He will get the seniority, and from the Created the juniority. But, in the nature of things, this cannot be; and so it must most certainly be true to affirm of the Holy Spirit one only of these alternatives, and that is, the attribute of being Uncreated; for notice the amount of absurdity involved in the other alternative; all things that we can think of in the actual creation have, by virtue of all having received their existence by an act of creation, a rank and value perfectly equal in all cases, and so what reason can there be for separating the Holy Spirit from the rest of the creation, and ranking Him with the Father and the Son? Logic, then, will discover this about Him; That which is contemplated as part of the Uncreated, does not exist by creation; or, if It does, then It has no more power than its kindred creation, It cannot associate itself with that Transcendent Nature; if, on the other hand, they declare that He is a created being, and at the same time has a power which is above the creation, then the creation will be found at variance with itself, divided into ruler and ruled, so that part of it is the benefactor, part the benefited, part the sanctifier, part the sanctified; and all that fund of blessings which we believe to be provided for the creation by the Holy Spirit are present in Him, welling up abundantly, and pouring forth upon others, while the creation remains in need of the thence-issuing help and grace, and receives, as a mere dole, those blessings which can be passed to it from a fellow-creature! That would be like favouritism and respecting of persons; when we know that there is no such partiality in the nature of things, as that those existences which differ in no way from each other on the score of substance should not have equal power; and I think that no one who reflects will admit such views. Either He imparts nothing to others, if He possesses nothing essentially; or, if we do believe that He does give, His possession beforehand of that gift must be granted; this capacity of giving blessings, while needing oneself no such extraneous help, is the peculiar and exquisite privilege of Deity, and of no other.
Then let us look to this too. In Holy Baptism, what is it that we secure thereby? Is it not a participation in a life no longer subject to death? I think that no one who can in any way be reckoned among Christians will deny that statement. What then? Is that life-giving power in the water itself which is employed to convey the grace of Baptism? Or is it not rather clear to every one that this element is only employed as a means in the external ministry, and of itself contributes nothing towards the sanctification, unless it be first transformed itself by the sanctification; and that what gives life to the baptized is the Spirit; as our Lord Himself says in respect to Him with His own lips, “It is the Spirit that gives life;” but for the completion of this grace He alone, received by faith, does not give life, but belief in our Lord must precede, in order that the lively gift may come upon the believer, as our Lord has spoken, “He gives life to whom He wills.” But further still, seeing that this grace administered through the Son is dependent on the Ungenerate Source of all, Scripture accordingly teaches us that belief in the Father Who engenders all things is to come first; so that this life-giving grace should be completed, for those fit to receive it, after starting from that Source as from a spring pouring life abundantly, through the Only-begotten Who is the True life, by the operation of the Holy Spirit. If, then, life comes in baptism, and baptism receives its completion in the name of Father, Son, and Spirit, what do these men mean who count this Minister of life as nothing? If the gift is a slight one, they must tell us the thing that is more precious than this life. But if everything whatever that is precious is second to this life, I mean that higher and precious life in which the brute creation has no part, how can they dare to depreciate so great a favour, or rather the actual Being who grants the favour, and to degrade Him in their conceptions of Him to a subject world by disjoining Him from the higher world of deity. Finally, if they will have it that this bestowal of life is a small thing, and that it means nothing great and awful in the nature of the Bestower, how is it they do not draw the conclusion which this very view makes inevitable, namely, that we must suppose, even with regard to the Only-begotten and the Father Himself, nothing great in Their life, the same as that which we have through the Holy Spirit, supplied as it is from the Father through the Son?
So that if these despisers and impugners of their very own life conceive of the gift as a little one, and decree accordingly to slight the Being who imparts the gift, let them be made aware that they cannot limit to one Person only their ingratitude, but must extend its profanity beyond the Holy Spirit to the Holy Trinity Itself. For like as the grace flows down in an unbroken stream from the Father, through the Son and the Spirit, upon the persons worthy of it, so does this profanity return backward, and is transmitted from the Son to the God of all the world, passing from one to the other. If, when a man is slighted, He Who sent him is slighted (yet what a distance there was between the man and the Sender!), what criminality is thereby implied in those who thus defy the Holy Spirit! Perhaps this is the blasphemy against our Law-giver for which the judgment without remission has been decreed; since in Him the entire Being, Blessed and Divine, is insulted also. As the devout worshipper of the Spirit sees in Him the glory of the Only-begotten, and in that sight beholds the image of the Infinite God, and by means of that image makes an outline, upon his own cognition, of the Original, so most plainly does this contemner (of the Spirit), whenever he advances any of his bold statements against the glory of the Spirit, extend, by virtue of the same reasoning, his profanity to the Son, and beyond Him to the Father. Therefore, those who reflect must have fear lest they perpetrate an audacity the result of which will be the complete blotting out of the perpetrator of it; and while they exalt the Spirit in the naming, they will even before the naming exalt Him in their thought, it being impossible that words can mount along with thought; still when one shall have reached the highest limit of human faculties, the utmost height and magnificence of idea to which the mind can ever attain, even then one must believe it is far below the glory that belongs to Him, according to the words in the Psalms, that “after exalting the Lord our God, even then ye scarcely worship the footstool beneath His feet”: and the cause of this dignity being so incomprehensible is nothing else than that He is holy.
Source: On the Holy Spirit (Against the Followers of Macedonius) (New Advent)