Bede the Venerable
Catena Aurea · Lukasevangelium 1
And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. For with God nothing shall be impossible. And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her.
So it was then, lest the virgin should despair of being able to bear a son, that she received the example of one both old and barren about to bring forth, in order that she might learn that all things are possible with God, even those which seem to be opposed to the order of nature. Whence it follows, For there shall be no word (verbum) impossible with God.