"Impeccability is predicated also of Mary on account of her superhuman dignity as the Mother of God, on account of her exemption from original sin and, consequently, from the foment of concupiscence, and on account of the fullness of grace with which her soul was adorned. But Mary’s impeccability was not intrinsic like Jesus’, but extrinsic rather, i.e., due to a special assistance of God."
Peitro Cardinal Parente, Antonio Piolanti, and Salvatore Garofalo
Dictionary of Dogmatic Theology
(Milwaukee: Bruce Publishing Company, 1951)