I will put enmity between you and the woman,
and between your offspring and hers;
he will strike your head,
and you will strike his heel.
The above passage is known as the Protoevangelium, the first gospel, the original good news. It is God’s promise that Satan, represented by the serpent, will be utterly defeated. His head will be crushed.
“An angel fell from Heaven without any other passion except pride, and so we may ask whether it is possible to ascend to Heaven by humility alone, without any other of the virtues.”
St. John Climicus, Ladder of Divine Ascent
Some say that Lucifer’s pride puffed most against God when he was told God’s plan to become human in the Incarnation. In his way of thinking, such a plan was unworthy of God. (St. Peter had a similar reaction, rebuking Christ’s plan for the Passion: “God forbid, Lord! No such thing shall ever happen to you.” Jesus responded, “Get behind me, Satan!” Matthew 16:22-13) Besides, for Lucifer to serve God as Man would be far below his own perfection!
St. Thomas, in his examination of Satan’s motives (Summa Theologiae, I.63-64), cites Isaiah 14:13-14:
In your heart you said:
“I will scale the heavens;
Above the stars of God
I will set up my throne;
I will take my seat on the Mount of Assembly,
on the heights of Zaphon.
I will ascend above the tops of the clouds;
I will be like the Most High!”
I’m not sure what he hoped to accomplish in his rebellion. No plan of his could succeed against God. But having problems with pride myself, I know it’s not entirely reasonable.
Because of her part in God’s plan, and because of her own goodness, the demons’ logic would actually point to Mary as being higher than them. She has the most reason of any creature to rejoice in herself. She was conceived without sin, named “Full of Grace” by the angel, chosen to be the Mother of God’s only Son, espoused by the Holy Spirit, rules as Queen of the Angels, crowned Queen of Heaven and Earth… What greater honor has a creature ever merited?
But instead of pursuing her own greatness, she persevered in smallness. She was obedient, became a channel of grace to those around her, acted always in meekness. By her humility, she merited even more blessedness. And it is this apparent paradox that the demons fear.
Because of her goodness, Mary continues to undermine the power that the demons exercise over her children. Where the dark angels have been defeated and now work only out of spite, she works to complete God’s plans. Ever more successfully, she crushes the serpent’s head whenever he dares to show it.