Thirdly, that she might offer to God the free gift of her obedience: which she proved herself right ready to do, saying: "Behold the handmaid of the Lord."
Fourthly, in order to show that there is a certain spiritual wedlock between the Son of God and human nature. Wherefore in the Annunciation the Virgin's consent was besought in lieu of that of the entire human nature.
Reply Obj. 1: The prophecy of predestination is fulfilled without the causality of our will; not without its consent.
Reply Obj. 2: The Blessed Virgin did indeed believe explicitly in the future Incarnation; but, being humble, she did not think such high things of herself. Consequently she required instruction in this matter.
Reply Obj. 3: The spiritual conception of Christ through faith is preceded by the preaching of the faith, for as much as "faith is by hearing" (Rom. 10:17). Yet man does not know for certain thereby that he has grace; but he does know that the faith, which he has received, is true. _______________________
SECOND ARTICLE [III, Q. 30, Art. 2]
Whether the annunciation should have been made by an angel to the
Blessed Virgin?
Objection 1: It would seem that the Annunciation should not have been made by an angel to our Blessed Lady. For revelations to the highest angels are made immediately by God, as Dionysius says (Coel. Hier. vii). But the Mother of God is exalted above all the angels. Therefore it seems that the mystery of the Incarnation should have been announced to her by God immediately, and not by an angel.
Obj. 2: Further, if in this matter it behooved the common order to be observed, by which Divine things are announced to men by angels; in like manner Divine things are announced to a woman by a man: wherefore the Apostle says (1 Cor. 14:34, 35): "Let women keep silence in the churches . . . but if they would learn anything, let them ask their husbands at home." Therefore it seems that the mystery of the Incarnation should have been announced to the Blessed Virgin by some man: especially seeing that Joseph, her husband, was instructed thereupon by an angel, as is related (Matt. 1:20, 21)
Obj. 3: Further, none can becomingly announce what he knows not. But the highest angels did not fully know the mystery of the Incarnation: wherefore Dionysius says (Coel. Hier. vii) that the question, "Who is this that cometh from Edom?" (Isa. 63:1) is to be understood as made by them. Therefore it seems that the announcement of the Incarnation could not be made becomingly by any angel.