Secondly, he purposed to instruct her about the mystery of the Incarnation, which was to be fulfilled in her. This he did by foretelling the conception and birth, saying: "Behold, thou shalt conceive in thy womb," etc.; and by declaring the dignity of the child conceived, saying: "He shall be great"; and further, by making known the mode of conception, when he said: "The Holy Ghost shall come upon thee."
Thirdly, he purposed to lead her mind to consent. This he did by the instance of Elizabeth, and by the argument from Divine omnipotence.
Reply Obj. 1: To a humble mind nothing is more astonishing than to hear its own excellence. Now, wonder is most effective in drawing the mind's attention. Therefore the angel, desirous of drawing the Virgin's attention to the hearing of so great a mystery, began by praising her.
Reply Obj. 2: Ambrose says explicitly on Luke 1:34, that the Blessed Virgin did not doubt the angel's words. For he says: "Mary's answer is more temperate than the words of the priest. She says: How shall this be? He replies: Whereby shall I know this? He denies that he believes, since he denies that he knows this. She does not doubt fulfilment when she asks how it shall be done."
Augustine, however, seems to assert that she doubted. For he says (De Qq. Vet. et Nov. Test. qu. li): "To Mary, in doubt about the conception, the angel declares the possibility thereof." But such a doubt is one of wonder rather than of unbelief. And so the angel adduces a proof, not as a cure for unbelief, but in order to remove her astonishment.
Reply Obj. 3: As Ambrose says (Hexaemeron v): "For this reason had many barren women borne children, that the virginal birth might be credible."
The conception of the sterile Elizabeth is therefore adduced, not as a sufficient argument, but as a kind of figurative example: consequently in support of this instance, the convincing argument is added taken from the Divine omnipotence. _______________________
QUESTION 31
OF THE MATTER FROM WHICH THE SAVIOUR'S BODY WAS CONCEIVED
(In Eight Articles)
We have now to consider the Saviour's conception. First, as to the matter from which His body was conceived; secondly, as to the author of His conception; thirdly, as to the manner and order of His conception.