But since our system of religion is wont to observe a distinction of persons in the unity of the Nature, to prevent our argument in our contention with Greeks sinking to the level of Judaism there is need again of a distinct technical statement in order to correct all error on this point.
For not even by those who are external to our doctrine is the Deity held to be without Logos. Now this admission of theirs will quite enable our argument to be unfolded. For he who admits that God is not without Logos, will agree that a being who is not without Logos (or word) certainly possesses Logos. Now it is to be observed that the utterance of man is expressed by the same term. If, then, he should say that he understands what the Logos of God is according to the analogy of things with us, he will thus be led on to a loftier idea, it being an absolute necessity for him to believe that the utterance, just as everything else, corresponds with the nature. Though, that is, there is a certain sort of force, and life, and wisdom, observed in the human subject, yet no one from the similarity of the terms would suppose that the life, or power, or wisdom, were in the case of God of such a sort as that, but the significations of all such terms are lowered to accord with the standard of our nature. For since our nature is liable to corruption and weak, therefore is our life short, our strength unsubstantial, our word unstable. But in that transcendent nature, through the greatness of the subject contemplated, every thing that is said about it is elevated with it. Therefore though mention be made of God's Word it will not be thought of as having its realization in the utterance of what is spoken, and as then vanishing away, like our speech, into the nonexistent. On the contrary, as our nature, liable as it is to come to an end, is endued with speech which likewise comes to an end, so that, imperishable and ever-existing nature has eternal, and substantial speech. If, then, logic requires him to admit this eternal subsistence of God's Word, it is altogether necessary to admit also that the subsistence of that word consists in a living state; for it is an impiety to suppose that the Word has a soulless subsistence after the manner of stones. But if it subsists, being as it is something with intellect and without body, then certainly it lives, whereas if it be divorced from life, then as certainly it does not subsist; but this idea that the Word of God does not subsist, has been shown to be blasphemy. By consequence, therefore, it has also been shown that the Word is to be considered as in a living condition. And since the nature of the Logos is reasonably believed to be simple, and exhibits in itself no duplicity or combination, no one would contemplate the existence of the living Logos as dependent on a mere participation of life, for such a supposition, which is to say that one thing is within another, would not exclude the idea of compositeness; but, since the simplicity has been admitted, we are compelled to think that the Logos has an independent life, and not a mere participation of life. If, then, the Logos, as being life, lives, it certainly has the faculty of will, for no one of living creatures is without such a faculty. Moreover that such a will has also capacity to act must be the conclusion of a devout mind. For if you admit not this potency, you prove the reverse to exist. But no; impotence is quite removed from our conception of Deity. Nothing of incongruity is to be observed in connection with the Divine nature, but it is absolutely necessary to admit that the power of that word is as great as the purpose, lest mixture, or concurrence, of contradictions be found in an existence that is incomposite, as would be the case if, in the same purpose, we were to detect both impotence and power, if, that is, there were power to do one thing, but no power to do something else. Also we must suppose that this will in its power to do all things will have no tendency to anything that is evil (for impulse towards evil is foreign to the Divine nature), but that whatever is good, this it also wishes, and, wishing, is able to perform, and, being able, will not fail to perform; but that it will bring all its proposals for good to effectual accomplishment. Now the world is good, and all its contents are seen to be wisely and skilfully ordered. All of them, therefore, are the works of the Word, of one who, while He lives and subsists, in that He is God's Word, has a will too, in that He lives; of one too who has power to effect what He wills, and who wills what is absolutely good and wise and all else that connotes superiority. Whereas, then, the world is admitted to be something good, and from what has been said the world has been shown to be the work of the Word, who both wills and is able to effect the good, this Word is other than He of whom He is the Word. For this, too, to a certain extent is a term of “relation,” inasmuch as the Father of the Word must needs be thought of with the Word, for it would not be word were it not a word of some one. If, then, the mind of the hearers, from the relative meaning of the term, makes a distinction between the Word and Him from whom He proceeds, we should find that the Gospel mystery, in its contention with the Greek conceptions, would not be in danger of coinciding with those who prefer the beliefs of the Jews. But it will equally escape the absurdity of either party, by acknowledging both that the living Word of God is an effective and creative being, which is what the Jew refuses to receive, and also that the Word itself, and He from whom He is, do not differ in their nature. As in our own case we say that the word is from the mind, and no more entirely the same as the mind, than altogether other than it (for, by its being from it, it is something else, and not it; still by its bringing the mind in evidence it can no longer be considered as something other than it; and so it is in its essence one with mind, while as a subject it is different), in like manner, too, the Word of God by its self-subsistence is distinct from Him from whom it has its subsistence; and yet by exhibiting in itself those qualities which are recognized in God it is the same in nature with Him who is recognizable by the same distinctive marks. For whether one adopts goodness, or power, or wisdom, or eternal existence, or the incapability of vice, death, and decay, or an entire perfection, or anything whatever of the kind, to mark one's conception of the Father, by means of the same marks he will find the Word that subsists from Him.
Source: The Great Catechism (New Advent)