He has no right to assert a greater and less in the Divine being. A systematic statement of the teaching of the Church
Then they discover in His being a certain shortness in the way of deficiency, though they do not tell us by what method they measure that which is devoid of quantity and size: they are able to find out exactly by how much the size of the Only-begotten falls short of perfection, and therefore has to be classed with the inferior and imperfect: much else they lay down, partly by open assertion, partly by underhand inference: all the time making their confession of the Son and the Spirit a mere exercise-ground for their unbelieving spirit. How, then, can we fail to pity them more even than the condemned Jews, when views never ventured upon by the latter are inferred by the former? He who makes the being of the Son and of the Spirit comparatively less, seems, so far as words go perhaps, to commit but a slight profanity: but if one were to test his view stringently it will be found the height of blasphemy. Let us look into this, then, and let indulgence be shown me, if, for the sake of doctrine, and to place in a clear light the lie which they have demonstrated, I advance into an exposition of our own conception of the truth.
Now the ultimate division of all being is into the Intelligible and the Sensible. The Sensible world is called by the Apostle broadly “that which is seen.” For as all body has colour, and the sight apprehends this, he calls this world by the rough and ready name of “that which is seen,” leaving out all the other qualities, which are essentially inherent in its framework. The common term, again, for all the intellectual world, is with the Apostle “that which is not seen:” by withdrawing all idea of comprehension by the senses he leads the mind on to the immaterial and intellectual. Reason again divides this “which is not seen” into the uncreate and the created, inferentially comprehending it: the uncreate being that which effects the Creation, the created that which owes its origin and its force to the uncreate. In the Sensible world, then, is found everything that we comprehend by our organs of bodily sense, and in which the differences of qualities involve the idea of more and less, such differences consisting in quantity, quality, and the other properties.
But in the Intelligible world—that part of it, I mean, which is created,— the idea of such differences as are perceived in the Sensible cannot find a place: another method, then, is devised for discovering the degrees of greater and less. The fountain, the origin, the supply of every good is regarded as being in the world that is uncreate, and the whole creation inclines to that, and touches and shares the Highest Existence only by virtue of its part in the First Good: therefore it follows from this participation in the highest blessings varying in degree according to the amount of freedom in the will that each possesses, that the greater and less in this creation is disclosed according to the proportion of this tendency in each. Created intelligible nature stands on the borderline between good and the reverse, so as to be capable of either, and to incline at pleasure to the things of its choice, as we learn from Scripture; so that we can say of it that it is more or less in the heights of excellence only in proportion to its removal from the evil and its approach to the good. Whereas uncreate intelligible nature is far removed from such distinctions: it does not possess the good by acquisition, or participate only in the goodness of some good which lies above it: in its own essence it is good, and is conceived as such: it is a source of good, it is simple, uniform, incomposite, even by the confession of our adversaries. But it has distinction within itself in keeping with the majesty of its own nature, but not conceived of with regard to quantity, as Eunomius supposes: (indeed the man who introduces the notion of less of good into any of the things believed to be in the Holy Trinity must admit thereby some admixture of the opposite quality in that which fails of the good: and it is blasphemous to imagine this in the case either of the Only-begotten, or of the Holy Spirit): we regard it as consummately perfect and incomprehensibly excellent yet as containing clear distinctions within itself which reside in the peculiarities of each of the Persons: as possessing invariableness by virtue of its common attribute of uncreatedness, but differentiated by the unique character of each Person. This peculiarity contemplated in each sharply and clearly divides one from the other: the Father, for instance, is uncreate and ungenerate as well: He was never generated any more than He was created. While this uncreatedness is common to Him and the Son, and the Spirit, He is ungenerate as well as the Father. This is peculiar and uncommunicable, being not seen in the other Persons. The Son in His uncreatedness touches the Father and the Spirit, but as the Son and the Only-begotten He has a character which is not that of the Almighty or of the Holy Spirit. The Holy Spirit by the uncreatedness of His nature has contact with the Son and Father, but is distinguished from them by His own tokens. His most peculiar characteristic is that He is neither of those things which we contemplate in the Father and the Son respectively. He is simply, neither as ungenerate, nor as only-begotten: this it is that constitutes His chief peculiarity. Joined to the Father by His uncreatedness, He is disjoined from Him again by not being 'Father.' United to the Son by the bond of uncreatedness, and of deriving His existence from the Supreme, He is parted again from Him by the characteristic of not being the Only-begotten of the Father, and of having been manifested by means of the Son Himself. Again, as the creation was effected by the Only-begotten, in order to secure that the Spirit should not be considered to have something in common with this creation because of His having been manifested by means of the Son, He is distinguished from it by His unchangeableness, and independence of all external goodness. The creation does not possess in its nature this unchangeableness, as the Scripture says in the description of the fall of the morning star, the mysteries on which subject are revealed by our Lord to His disciples: “I saw Satan falling like lightning from heaven.” But the very attributes which part Him from the creation constitute His relationship to the Father and the Son. All that is incapable of degenerating has one and the same definition of “unchangeable.”
Having stated thus much as a preface we are in a position to discuss the rest of our adversaries' teaching. “It necessarily follows,” he says in his system of the Son and the Spirit, “that the Beings are relatively greater and less.” Let us then inquire what is the meaning of this necessity of difference. Does it arise from a comparison formed from measuring them one with another in some material way, or from viewing them on the spiritual ground of more or less of moral excellence, or on that of pure being? But in the case of this last it has been shown by competent thinkers that it is impossible to conceive of any difference whatever, if one abstracts being from attributes and properties, and looks at it according to its bare definition. Again, to conceive of this difference as consisting in the case of the Only-begotten and the Spirit in the intensity or abatement of moral excellence, and in consequence to hint that their nature admits of change in either direction, so as to be equally capable of opposites, and to be placed in a borderland between moral beauty and its opposite— that is gross profanity. A man who thinks this will be proving that their nature is one thing in itself, and becomes something else by virtue of its participation in this beauty or its opposite: as happens with iron for example: if it is approached some time to the fire, it assumes the quality of heat while remaining iron: if it is put in snow or ice, it changes its quality to the mastering influence, and lets the snow's coldness pass into its pores.
Source: Against Eunomius (New Advent)