Ambrose of Milan — as excerpted in the Catena Aurea on Luke 1:15-17

“Next to his becoming the rejoicing of many, the greatness of his virtue is prophesied; as it is said, For he shall be great in the sight of the Lord. The greatness signified is not of the body, but of the soul. Greatness in the sight of the Lord is greatness of soul, greatness of virtue.”