All this; τοῦτο ὅλον (not ταῦτα πάντα). The birth of a Saviour, with the means by which it came about, by a virgin, and "of the Holy Ghost." Was done; is come to pass (Revised Version); i.e. in abiding effect ( γέγονεν).
It is considered as having already taken place (cf. "the prophetic perfect" of the Old Testament). That it might be fulfilled. God's past utterance is looked at as necessitating a present action. Which was spoken of the Lord by the prophet, saying; by the Lord through (Revised Version); i.
e. the Lord is the Agent ( ὑπό), the prophet the means or instrument ( διά). The Lord; i.e. Jehovah, not "God," because the thought is of covenant promise.