St. Bernard on the Annunciation

Hail, thou who art full of grace; the Lord is with thee. The angel did not say, "The Lord is in thee," but The Lord is with thee. God is: wholly present everywhere as far as his substance is concerned,' but he is not present in the same way in rational creatures as he is in others. Even among rational creatures his presence differs in different cases, for it is not felt by the wicked in the way it is by the good. As for creatures without reason, God is present in them but they cannot grasp the fact. It is possible for all rational beings to obtain a certain grasp of God through the knowledge they have Of him, but only the good can grasp him by love as well. Thus, only in the good is he present in such a way as to be with them, because his will and theirs are then in harmony with each other, When they submit their wills to the demands of morality, it is not unreasonable that God should will what they will: by not dissenting from his will, they bring God particularly close to them.

Although this is the case with all the saints, it was especially so with Mary. So close was God to her that not content with taking her will, he even took her flesh and from her substance and his own made, or rather became, the Christ. The one Christ came from the two of them. He did not come exclusively from God or exclusively from Mary, but he was exclusively the work of them both. There were not two Sons; there was only one, and he was God's Son and Mary's.

That was why the angel said: Hail, thou who art full of grace; the Lord is with thee. The Lord that was with her was not only the Son she clothed with her flesh, but the Holy Spirit by whom she conceived and the Father who begot the Son she conceived. The Father was with her because he made his own Son to be her Son too. The Son was with her because he accomplished this wonderful mystery in her, miraculously unlocking for himself the secret place of generation and leaving her the sign of virginity on the door. The Holy Spirit was with her because with the Father and the Son he sanctified her womb. In these ways was the Lord with her.