He proceeds to discuss the views held by Eunomius, and by the Church, touching the Holy Spirit; and to show that the Father, the Son, and the Holy Ghostare not three Gods, but one God. He also discusses different senses of Subjection, and therein shows that the subjection of all things to the Son is the same as the subjection of the Son to the Father
Let us however resume Eunomius' statement in its entirety. “Having come into being from the only God through the Only-begotten, this Spirit also—” What proof is there of the statement that “this Spirit also” is one of the things that were made by the Only-begotten? They will say of course that “all things were made by Him,” and that in the term “all things” “this Spirit also” is included. Our answer to them shall be this, All things were made by Him, that were made. Now the things that were made, as Paul tells us, were things visible and invisible, thrones, authorities, dominions, principalities, powers, and among those included under the head of thrones and powers are reckoned by Paul the Cherubim and Seraphim: so far does the term “all things” extend.
But of the Holy Spirit, as being above the nature of things that have come into being, Paul said not a word in his enumeration of existing things, not indicating to us by his words either His subordination or His coming into being; but just as the prophet calls the Holy Spirit “good,” and “right,” and “guiding” (indicating by the word “guiding” the power of control), even so the apostle ascribes independent authority to the dignity of the Spirit, when he affirms that He works all in all as He wills. Again, the Lord makes manifest the Spirit's independent power and operation in His discourse with Nicodemus, when He says, “The Spirit breathes where He wills.”
How is it then that Eunomius goes so far as to define that He also is one of the things that came into being by the Son, condemned to eternal subjection. For he describes Him as “once for all made subject,” enthralling the guiding and governing Spirit in I know not what form of subjection. For this expression of “subjection” has many significations in Holy Scripture, and is understood and used with many varieties of meaning. For the Psalmist says that even irrational nature is put in subjection, and brings under the same term those who are overcome in war, while the apostle bids servants to be in subjection to their own masters, and that those who are placed over the priesthood should have their children in subjection, as their disorderly conduct brings discredit upon their fathers, as in the case of the sons of Eli the priest.
Again, he speaks of the subjection of all men to God, when we all, being united to one another by the faith, become one body of the Lord Who is in all, as the subjection of the Son to the Father, when the adoration paid to the Son by all things with one accord, by things in heaven, and things on earth, and things under the earth, redounds to the glory of the Father; as Paul says elsewhere, “To Him every knee shall bow, of things in heaven, and things in earth, and things under the earth, and every tongue shall confess that Jesus Christ is Lord, to the glory of God the Father.”
For when this takes place, the mighty wisdom of Paul affirms that the Son, Who is in all, is subject to the Father by virtue of the subjection of those in whom He is. What kind of “subjection once for all” Eunomius asserts of the Holy Spirit, it is thus impossible to learn from the phrase which he has thrown out—whether he means the subjection of irrational creatures, or of captives, or of servants, or of children who are kept in order, or of those who are saved by subjection.
For the subjection of men to God is salvation for those who are so made subject, according to the voice of the prophet, who says that his soul is subject to God, since of Him comes salvation by subjection, so that subjection is the means of averting perdition. As therefore the help of the healing art is sought eagerly by the sick, so is subjection by those who are in need of salvation. But of what life does the Holy Spirit, that quickens all things, stand in need, that by subjection He should obtain salvation for Himself?
Since then it is not on the strength of any Divine utterance that he asserts such an attribute of the Spirit, nor yet is it as a consequence of probable arguments that he has launched this blasphemy against the Holy Spirit, it must be plain at all events to sensible men that he vents his impiety against Him without any warrant whatsoever, unsupported as it is by any authority from Scripture or by any logical consequence.
Source: Against Eunomius (New Advent)