Among all sacred things, the devil most fears the Most Holy Name of Mary.
When we speak of the Blessed Virgin Mary and Lucifer, we speak of two creatures, that is, created by God: one human and the other angelic. And yet, their existence is the exact opposite. Mary loved God and surrendered to His will and the devil rebelled.
6 reasons the devil flees before the Most Holy Name of Mary
By invoking the Holy Name of Mary, the devil flees due to her holiness and humility.
Our Lady was born a humble and fragile human being.
“It is true that the Creator, as soon as she was born, must have granted great perfections to her soul, but these perfections were far from the immense power possessed by the splendor of Creation, the highest angelic spirit”, former exorcist Father José Antonio Fortea said in his book, "Summa Daemoniaca."
“God created Lucifer magnificent in his nature and he became corrupted. God created Mary humble in her nature, a mere woman, and therefore lower than the angels, and it was she who sanctified herself," the priest added.
This is primarily why the devil hates and fears the Holy Name of Mary. He was given so much according to his nature and he became a moral monster. The Virgin was born with a humble nature, but grace sanctified her as the Queen of Heaven.
Everything the devil sees in the Blessed Virgin Mary reminds him of his rebellion and fall. This is how Father Fortea describes it:
1) Lucifer wanted to be king and serve no one, and ended up being nothing. Mary wanted to be little and serve, and in the end, she is queen.
2) The devil was created as the angelic Morning Star. She (Mary) turned out to be the Morning Star of Redemption, that is, the star that in the firmament announces the new age of the Messiah.
3) The devil fell from the angelic firmament. Mary was the star that appeared in the firmament of the saints.
4) Lucifer did not want to accept the Son of God made man. The Virgin not only accepted him but also welcomed him into her bosom.
5) The demon was a spiritual being that eventually became worse than a beast (still being spiritual).
6) Mary was a material being who eventually became better than an angel (even though she was material).
These are the reasons why the devil flees before the Holy Name of Mary.