Bede the Venerable

If you diligently examine the words of the law, you will find indeed that the mother of God as she is free from all connexion with man, so is she exempt from any obligation of the law. For not every woman who brings forth, but she who has received seed and brought forth, is pronounced unclean, and by the ordinances of the law is taught that she must be cleansed, in order to distinguish probably from her who though a virgin has conceived and brought forth. But that we might be loosed from the bonds of the law, as did Christ, so also Mary submitted herself of her own will to the law.