The eternal Father was also to create her in his grace, because he predestined her to be the repairer of the lost world, the mediator of peace between God and mankind. This is what the holy Fathers call her, especially St. John Damascene, who says to her: "Blessed Virgin, you were created and born to procure salvation for the whole earth. For this reason, says St. Bernard, Mary was prefigured in Noah's ark; just as through her men were saved from the flood, so through Mary we are saved from being shipwrecked in sin; but with the difference that through the ark a few were saved, but through Mary the whole human race has been liberated. St. Athanasius calls her our Eve, because the former was the mother of death, while the Blessed Virgin is the mother of life. St. Theophilus, bishop of Nicaea, says to her: "Hail, you who destroyed the sadness of Eve". St. Basil calls her the advocate between men and God; and St. Ephrem the reconciler of the whole world.
Now, he who deals with matters of peace can in no way be the enemy of the offended, much less an accomplice in the same crime. To placate a judge, the least appropriate person is an enemy of his, since instead of placating him, he would irritate him more. Therefore, since Mary had to be the mediator of peace between men and God, the most elementary reason demands that she should never have been a sinner and an enemy of God, but rather his friend and absolutely clean of all sin.
Moreover, God had to preserve her from the original guilt, for she was predestined to break the head of the infernal serpent, the one who, by seducing the first parents, brought death to all men. God prophesied: "I will put enmity between you and the woman, between your offspring and hers: she shall bruise your head" (Gen 3:15). If Mary was to be the strong woman placed in the world to overcome Lucifer, it is evident that she could not be overcome by him and made his slave; on the contrary, she had to be exempt from all stain of sin and from any form of subjection to the enemy. The proud one, as he had infected the whole human race with his poison, would desire, more than anything else, to infect the most pure soul of this Virgin. But may the divine goodness be praised forever, who, for this reason, endowed her with so much grace that, since she was immune from all traces of guilt, she was thus able to abate and confound the enemy's pride. This is how St. Bonaventure explains it: "Since the diabolical head was the cause of sin, it could not enter the soul of the Virgin, and for this reason she was immune to every stain". And further on he clarifies it as follows: "It was entirely congruent that the Blessed Virgin Mary, through whom opprobrium was wrested from us, conquered the devil, and did not succumb to him in the least".
Las Glorias de María. San Alfonso M Ligorio