Chapter 44 — That the human nature assumed by the Word was perfect in body and soul at the moment of conception

Hence it follows that the rational soul was united to the body at the very beginning of the conception.

The Word of God assumed the body through the medium of the rational soul, because the human body is not more adapted to be assumed by God than other bodies except on account of the rational soul. Therefore, the Word of God did not assume a body without a rational soul. Since, then, the Word of God assumed the body at the very moment of its conception, it follows that at that very moment the rational soul was united to the body.

Again. Given that which comes later in the process of generation, we must grant what comes before in that process. Now the last thing in the process of generation is a complete being, and this complete being is the individual thing generated, which in human generation is a hypostasis or person for the completion of which both a soul and body are required. Given, then, the personality of the man that is begotten, both rational soul and body must be in existence. Now the personality of the man Christ is no other than the personality of the Word of God, and the Word of God took to himself a human body in the very moment of conception. Therefore, the personality of that man was there. Consequently, the rational soul must have been there also.

It would, moreover, have been unbecoming for the Word, who is the fount and origin of all perfections and forms, to be united to that which lacked form and natural perfection. Now a body in the making is, before animation, without form and natural perfection. Therefore, it was unfitting for the Word of God to be united to a body without a soul. Consequently, that soul had to be united to the body from the very beginning of conception.

From this we may also conclude that the assumed body was formed from the very beginning of its conception, since it was not fitting for the Word of God to assume anything unformed. Now the soul, like any natural form, requires its proper matter, and the proper matter of the soul is a body with organs, since the soul is the active principle of a physical, organic body that is potentially a living being. Hence if, as already proved, (Ch. 43.) the soul was united to the body from the first moment of conception, it follows that this same body had limbs and form from the first moment of conception. Even in the order of generation the body is limbed before the advent of the rational soul: if this latter has taken place, the former must have taken place already.

Nor is there any reason why the body should not continue to grow until it has reached its appointed stage of development, even after the advent of the soul. Accordingly, with regard to the man assumed, we must hold that at the first moment of his conception, his body was limbed and formed, though it was not yet fully developed.