Against Eunomius

The first man, and the man born from him, received their being in a different way; the latter by copulation, the former from the moulding of Christ Himself; and yet, though they are thus believed to be two, they are inseparable in the definition of their being, and are not considered as two beings, without beginning or cause, running parallel to each other; nor can the existing one be said to be generated by the existing one, or the two be ever thought of as one in the monstrous sense that each is his own father, and his own son; but it is because the one and the other was a man that the two have the same definition of being; each was mortal, reasoning, capable of intuition and of science.

If, then, the idea of humanity in Adam and Abel does not vary with the difference of their origin, neither the order nor the manner of their coming into existence making any difference in their nature, which is the same in both, according to the testimony of every one in his senses, and no one, not greatly needing treatment for insanity, would deny it; what necessity is there that against the divine nature we should admit this strange thought? Having heard of Father and Son from the Truth, we are taught in those two subjects the oneness of their nature; their natural relation to each other expressed by those names indicates that nature; and so do Our Lord's own words.

For when He said, “I and My Father are one,” He conveys by that confession of a Father exactly the truth that He Himself is not a first cause, at the same time that He asserts by His union with the Father their common nature; so that these words of His secure our faith from the taint of heretical error on either side: for Sabellius has no ground for his confusion of the individuality of each Person, when the Only-begotten has so distinctly marked Himself off from the Father in those words, “I and My Father;” and Arius finds no confirmation of his doctrine of the strangeness of either nature to the other, since this oneness of both cannot admit distinction in nature.

For that which is signified in these words by the oneness of Father and Son is nothing else but what belongs to them on the score of their actual being; all the other moral excellences which are to be observed in them as over and above their nature may without error be set down as shared in by all created beings. For instance, Our Lord is called merciful and pitiful by the prophet, and He wills us to be and to be called the same; “Be therefore merciful,” and “Blessed are the merciful,” and many such passages.

If, then, any one by diligence and attention has modelled himself according to the divine will, and become kind and pitiful and compassionate, or meek and lowly of heart, such as many of the saints are testified to have become in the pursuit of such excellences, does it follow that they are therefore one with God, or united to Him by virtue of any one of them? Not so. That which is not in every respect the same, cannot be 'one' with him whose nature thus varies from it. Accordingly, a man becomes 'one' with another, when in will, as our Lord says, they are 'perfected into one,' this union of wills being added to the connection of nature.

So also the Father and Son are one, the community of nature and the community of will running, in them, into one. But if the Son had been joined in wish only to the Father, and divided from Him in His nature, how is it that we find Him testifying to His oneness with the Father, when all the time He was sundered from Him in the point most proper to Him of all?