John Chrysostom
Otherwise; the Angel seeing the depths of the Divine mercy, the laws of nature broken through and reconciliation made, He who was above all made lower than all; all these wonders, all this he comprises in that one saying, Now all this hath happened; as though he had said, Do not suppose that this is newly devised of God, it was determined of old. And he rightly cites the Prophet not to the Virgin, who as a maiden was untaught in such things, but to Joseph, as to one much versed in the Prophets. And at first he had spoken of Mary as thy wife, but now in the words of the Prophet he brings in the word “Virgin,” that he might hear this from the Prophet, as a thing long before determined. Therefore to confirm what he had said, he introduces Isaiah, or rather God; for he does not say, Which was spoken by Isaiah, but, Which was spoken of the Lord by the Prophet.
As it is the manner of Scripture to convey a knowledge of events under the form of a name, so here, They shall call His name Emmanuel, means nothing else than, They shall see God among men. Whence he says not, ‘Thou shalt call,’ but, They shall call.