St. Augustine on the Holiness of the Virgin

Blessed Augustine of Hippo ca. 354-430

With the exception of the holy Virgin Mary, in whose case, out of respect for the Lord, I do not wish there to be any further question as far as sin is concerned, since how can we know what great abundance of grace was conferred on her to conquer sin in every way, seeing that she merited to conceive and bear Him Who certainly had no sin at all. (De Natura et Gratia 36, 42)