Ambrose of Milan
Catena Aurea · Lukasevangelium 1
And the angel said unto her, Fear not, Mary: for thou hast found favour with God. And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS. He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end. When the angel saw that she was troubled at this unusual salutation, calling her by her name as if she was well known to him, he tells her she must not fear, as it follows; And the angel said, Fear not, Mary.
But all are not as Mary, that when they conceive the word of the Holy Spirit, they bring forth; for some put forth the word prematurely, others have Christ in the womb, but not yet formed.