The fourth book discusses the account of the nature of the product of generation, and of the passionless generation of the Only-Begotten, and the text, In the beginning was the Word, and the birth of the Virgin
It is, perhaps, time to examine in our discourse that account of the nature of the “product of generation” which is the subject of his ridiculous philosophizing. He says, then (I will repeat word for word his beautifully composed argument against the truth):— “Who is so indifferent and inattentive to the nature of things as not to know, that of all bodies which are on earth, in their generating and being generated, in their activity and passivity, those which generate are found on examination to communicate their own essence, and those which are generated naturally receive the same, inasmuch as the material cause and the supply which flows in from without are common to both; and the things begotten are generated by passion, and those which beget, naturally have an action which is not pure, by reason of their nature being linked with passions of all kinds?” See in what fitting style he discusses in his speculation the pre-temporal generation of the Word of God that was in the beginning! He who closely examines the nature of things, bodies on the earth, and material causes, and passion of things generating and generated, and all the rest of it—at which any man of understanding would blush, even were it said of ourselves, if it were our nature, subject as it is to passion, which is thus exposed to scorn by his words. Yet such is our author's brilliant enquiry into nature with regard to the Only-begotten God. Let us lay aside complaints, however, (for what will sighing do to help us to overthrow the malice of our enemy?) and make generally known, as best we may, the sense of what we have quoted— concerning what sort of “product” the speculation was proposed—that which exists according to the flesh, or that which is to be contemplated in the Only-begotten God.
As the speculation is two-fold, concerning that life which is Divine, simple, and immaterial, and concerning that existence which is material and subject to passion, and as the word “generation” is used of both, we must needs make our distinction sharp and clear, lest the ambiguity of the term “generation” should in any way pervert the truth. Since, then, the entrance into being through the flesh is material, and is promoted by passion, while that which is bodiless, impalpable, without form, and free from any material commixture, is alien from every condition that admits of passion, it is proper to consider about what sort of generation we are enquiring— that which is pure and Divine, or that which is subject to passion and pollution. Now, no one, I suppose, would deny that with regard to the Only-begotten God, it is pre-temporal existence that is proposed for the consideration of Eunomius' discourse. Why, then, does he linger over this account of corporeal nature, defiling our nature by the loathsome presentment of his argument, and setting forth openly the passions that gather round human generation, while he deserts the subject set before him? For it was not about this animal generation, that is accomplished by means of the flesh, that we had any need to learn. Who is so foolish, when he looks on himself, and considers human nature in himself, as to seek another interpreter of his own nature, and to need to be told all the unavoidable passions which are included in the thought of bodily generation— that he who begets is affected in one way, that which is begotten in another— so that the man should learn from this instruction that he himself begets by means of passion, and that passion was the beginning of his own generation? For it is all the same whether these things are passed over or spoken, and whether one publishes these secrets at length, or keeps hidden in silence things that should be left unsaid, we are not ignorant of the fact that our nature progresses by way of passion. But what we are seeking is that a clear account should be given of the exalted and unspeakable existence of the Only-begotten, whereby He is believed to be of the Father.
Now, while this is the enquiry set before him, our new theologian enriches his discourse with “flowing,” and “passion,” and “material cause,” and some “action” which “is not pure” from pollution, and all other phrases of this kind. I know not under what influence it is that he who says, in the superiority of his wisdom, that nothing incomprehensible is left beyond his own knowledge, and promises to explain the unspeakable generation of the Son, leaves the question before him, and plunges like an eel into the slimy mud of his arguments, after the fashion of that Nicodemus who came by night, who, when our Lord was teaching him of the birth from above, rushed in thought to the hollow of the womb, and raised a doubt how one could enter a second time into the womb, with the words, “How can these things be?” thinking that he would prove the spiritual birth impossible, by the fact that an old man could not again be born within his mother's bowels. But the Lord corrects his erroneous idea, saying that the properties of the flesh and the spirit are distinct. Let Eunomius also, if he will, correct himself by the like reflection. For he who ponders on the truth ought, I imagine, to contemplate his subject according to its own properties, not to slander the immaterial by a charge against things material. For if a man, or a bull, or any other of those things which are generated by the flesh, is not free from passion in generating or being generated, what has this to do with that Nature which is without passion and without corruption? The fact that we are mortal is no objection to the immortality of the Only-begotten, nor does men's propensity to vice render doubtful the immutability that is found in the Divine Nature, nor is any other of our proper attributes transferred to God; but the peculiar nature of the human and the Divine life is separated, and without common ground, and their distinguishing properties stand entirely apart, so that those of the latter are not apprehended in the former, nor, conversely, those of the former in the latter.
Source: Against Eunomius (New Advent)