14 Yet from these two comparisons, these two kinds, we may perhaps find in the creature a resemblance whereby we may understand how the Son is both coeternal with the Father, and in no respect less than He. But this we cannot find in one kind of resemblances singly: let us join both kinds together. How both kinds? One, of which they themselves give instances of resemblances, and the other, of which we gave. For they gave instances of resemblances from those things which are born in time, and are preceded in time by them of whom they are born, as man of man.
He that is born first is greater in time; but yet man and man, that is of the same substance. For man begets a man, and a horse a horse, and a sheep a sheep. These beget after the same substance, but not after the same time. They are diverse in time, but not in nature diverse. What then do we praise here in this nativity? The equality of nature surely. But what is wanting? The equality of time. Let us retain the one thing which is praised here, that is, the equality of nature.
But in the other kind of resemblances, which we gave from the brightness of the fire and the image of the shrub, you find not an equality of nature, you do find an equality of time. What do we praise here? Equality of time. What is wanting? Equality of nature. Join the things which you praise together. For in the creatures there is wanting something which you praise, in the Creator nothing can be wanting: because what you find in the creature, came forth from the Hand of the Creator.
What then is there in things coeval? Must not that be given to God which you praise here in? But what is wanting must not be attributed to that Sovereign Majesty, in the which there is no defect. See I offer to you things begetting coeval with things begotten: in these you praise the equality of time, but find fault with the inequality of nature. What you find fault with, do not attribute to God; what you praise, attribute to Him; so from this kind of resemblances you attribute to Him instead of a cotemporaneousness a coeternity, that the Son may be coeternal with Him of whom He was born.
But from the other kind of resemblances, which itself too is a creature of God, and ought to praise the Creator, what do you praise in them? Equality of nature. You had before assigned coeternity by reason of the first distinction; by reason of this last, assign equality; and the nativity of the same substance is complete. For what is more mad, my brethren, than that I should praise the creature in anything which does not exist in the Creator? In man I praise equality of nature, shall I not believe it in Him who made man?
That which is born of man is man; shall not that which is born of God, be That which He is of whom He was born? Converse have I none with works which God has not made. Let then all the works of the Creator praise Him. I find in the one case a cotemporaneousness, I get at the knowledge of a coeternity in the other. In the first I find an equality of nature, I understand an equality of substance in the other. In this then that is “wholly,” which in the other case is found in the several parts, and several things.
It is then “wholly” here altogether, and not only what is in the creature; I find it wholly here, but as being in the Creator, in so much higher a way, in that the one is visible, the Other Invisible; the one temporal, the Other Eternal; the one changeable, the Other Unchangeable; the one corruptible, the Other Incorruptible. Lastly, in the case of men themselves, what we find, man and man, are two men; here the Father and the Son are One God.
Source: Sermons on Selected Lessons of the New Testament (New Advent)