"God has established only one enmity - but it is an irreconcilable one - which will last and even go on increasing to the end of time. That enmity is between Mary, his worthy Mother, and the devil, between the children and the servants of the Blessed Virgin and the children and followers of Lucifer.
Thus the most fearful enemy that God has set up against the devil is Mary, his holy Mother. From the time of the earthly paradise, although she existed then only in his mind, he gave her such a hatred for his accursed enemy, such ingenuity in exposing the wickedness of the ancient serpent and such power to defeat, overthrow and crush this proud rebel, that Satan fears her not only more than angels and men but in a certain sense more than God himself. This does not mean that the anger, hatred and power of God are not infinitely greater than the Blessed Virgin's, since her attributes are limited. It simply means that Satan, being so proud, suffers infinitely more in being vanquished ang punished by a lowly and humble servant of God, for her humility humiliates him more than the power of God. Moreover, God has given Mary such great power over the evil spirits that, as they have often been forced unwillingly to admit through the lips of possessed persons, they fear one of her pleadings for a soul more than the prayers of all the saints, and one of her threats more than all their other torments.
What Lucifer lost by pride Mary won by humility."
- Excerpt from the book True Devotion to the Blessed Virgin, Author: St. Louis-Marie Grignion de Montfort