Reply Obj. 1: Temporal nativity would cause a real temporal filiation in Christ if there were in Him a subject capable of such filiation. But this cannot be; since the eternal suppositum cannot be receptive of a temporal relation, as stated above. Nor can it be said that it is receptive of temporal filiation by reason of the human nature, just as it is receptive of the temporal nativity; because human nature would need in some way to be the subject of filiation, just as in a way it is the subject of nativity; for since an Ethiopian is said to be white by reason of his teeth, it must be that his teeth are the subject of whiteness. But human nature can nowise be the subject of filiation, because this relation regards directly the person.
Reply Obj. 2: Eternal filiation does not depend on a temporal mother, but together with this eternal filiation we understand a certain temporal relation dependent on the mother, in respect of which relation Christ is called the Son of His Mother.
Reply Obj. 3: One and being are mutually consequent, as is said Metaph. iv. Therefore, just as it happens that in one of the extremes of a relation there is something real, whereas in the other there is not something real, but merely a certain aspect, as the Philosopher observes of knowledge and the thing known; so also it happens that on the part of one extreme there is one relation, whereas on the part of the other there are many. Thus in man on the part of his parents there is a twofold relation, the one of paternity, the other of motherhood, which are specifically diverse, inasmuch as the father is the principle of generation in one way, and the mother in another (whereas if many be the principle of one action and in the same way—for instance, if many together draw a ship along—there would be one and the same relation in all of them); but on the part of the child there is but one filiation in reality, though there be two in aspect, corresponding to the two relations in the parents, as considered by the intellect. And thus in one way there is only one real filiation in Christ, which is in respect of the Eternal Father: yet there is another temporal relation in regard to His temporal mother. _______________________
SIXTH ARTICLE [III, Q. 35, Art. 6]
Whether Christ Was Born Without His Mother Suffering?
Objection 1: It would seem that Christ was not born without His Mother suffering. For just as man's death was a result of the sin of our first parents, according to Gen. 2:17: "In what day soever ye shall eat, ye shall [Vulg.: 'thou shalt eat of it, thou shalt] die"; so were the pains of childbirth, according to Gen. 3:16: "In sorrow shalt thou bring forth children." But Christ was willing to undergo death. Therefore for the same reason it seems that His birth should have been with pain.
Obj. 2: Further, the end is proportionate to the beginning. But
Christ ended His life in pain, according to Isa. 53:4: "Surely . . .
He hath carried our sorrows." Therefore it seems that His nativity
was not without the pains of childbirth.
Obj. 3: Further, in the book on the birth of our Saviour [*Protevangelium Jacobi xix, xx] it is related that midwives were present at Christ's birth; and they would be wanted by reason of the mother's suffering pain. Therefore it seems that the Blessed Virgin suffered pain in giving birth to her Child.
On the contrary, Augustine says (Serm. de Nativ. [*Supposititious]), addressing himself to the Virgin-Mother: "In conceiving thou wast all pure, in giving birth thou wast without pain."
I answer that, The pains of childbirth are caused by the infant opening the passage from the womb. Now it has been said above (Q. 28, A. 2, Replies to objections), that Christ came forth from the closed womb of His Mother, and, consequently, without opening the passage. Consequently there was no pain in that birth, as neither was there any corruption; on the contrary, there was much joy therein for that God-Man "was born into the world," according to Isa. 35:1, 2: "Like the lily, it shall bud forth and blossom, and shall rejoice with joy and praise."