But, it is said, to be born and to die are conditions peculiar to the fleshly nature. I admit it. But what went before that Birth and what came after that Death escapes the mark of our common humanity. If we look to either term of our human life, we understand both from what we take our beginning, and in what we end. Man commenced his existence in a weakness and in a weakness completes it. But in the instance of the Incarnation neither did the birth begin with a weakness, nor in a weakness did the death terminate; for neither did sensual pleasure go before the birth, nor did corruption follow upon the death.
Do you disbelieve this marvel? I quite welcome your incredulity. You thus entirely admit that those marvellous facts are supernatural, in the very way that you think that what is related is above belief. Let this very fact, then, that the proclamation of the mystery did not proceed in terms that are natural, be a proof to you of the manifestation of the Deity. For if what is related of Christ were within the bounds of nature, where were the Godhead? But if the account surpasses nature, then the very facts which you disbelieve are a demonstration that He who was thus proclaimed was God.
A man is begotten by the conjunction of two persons, and after death is left in corruption. Had the Gospel comprised no more than this, you certainly would not have deemed him to be God, the testimony to whom was conveyed in terms peculiar only to our nature. But when you are told that He was born, and yet transcended our common humanity both in the manner of His birth, and by His incapacity of a change to corruption, it would be well if, in consequence of this, you would direct your incredulity upon the other point, so as to refuse to suppose Him to be one of those who have manifestly existed as mere men; for it follows of necessity that a person who does not believe that such and such a being is mere man, must be led on to the belief that He is God.
Well, he who has recorded that He was born has related also that He was born of a Virgin. If, therefore, on the evidence stated, the fact of His being born is established as a matter of faith, it is altogether incredible, on the same evidence, that He was not born in the manner stated. For the author who mentions His birth adds also, that it was of a Virgin; and in recording His death bears further testimony to His resurrection from the dead. If, therefore, from what you are told, you grant that He both was born and died, on the same grounds you must admit that both His birth and death were independent of the conditions of human weakness—in fact, were above nature.
The conclusion, therefore, is that He Who has thus been shown to have been born under supernatural circumstances was certainly Himself not limited by nature.
Source: The Great Catechism (New Advent)