There Lewis said,
According to Christian teachers, the essential vice, the utmost evil, is Pride. Unchastity, anger, greed, drunkenness, and all that, are mere flea bites in comparison: it was through Pride that the devil became the devil
Pride first appears in the Bible in Genesis 3, where we see the devil, that “proud spirit” as John Donne described him, using pride as the avenue by which to seduce our first parents. Taking the form of a serpent, his approach was simple yet deadly. First, he arrogantly contradicted what God had said to Eve about eating the forbidden fruit and charged God with lying.
This shocking rejection of God’s word introduced Eve to the hitherto unknown possibility of unbelief and was intended to arouse doubt in her mind about the truthfulness and reliability of God. In the next breath, the devil drew her into deeper deception by contending that God’s reason for lying was to keep her from enjoying all the possibilities inherent in being Godlike. This clever ploy was aimed at undermining her confidence in the goodness and love of God and arousing the desire to become as God.
The desire to lift up and exalt ourselves beyond our place as God’s creature lies at the heart of pride. As Eve in her now confused and deceived state of mind considered the possibilities, her desire to become Godlike grew stronger. She began to look at the forbidden fruit in a new light, as something attractive to the eyes and pleasant to the touch. Desire increased, giving rise to rationalization and a corresponding erosion of the will to resist and say no.
Finally, weakened by unbelief, enticed by pride, and ensnared by self-deception, she opted for autonomy and disobeyed God’s command. In just a few deft moves, the devil was able to use pride to bring about Eve’s downfall and plunge the human race into spiritual ruin. This ancient but all-too-familiar process confronts each of us daily: “Each person is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death” (James 1:14–15).
From this point on in the Bible, we see the outworking of pride and unbelief in the affairs of individuals, families, nations, and cultures. As people lose or suppress the knowledge of God, spiritual darkness grows and a psychological inversion occurs: in their thinking God becomes smaller and they become larger. The center of gravity in their mental lives shifts from God to themselves. They become the center of their world, and God is conveniently moved to the periphery, either through denial of his existence or distortion of his character. Self-importance and godless self-confidence grow stronger. The cycle that follows is familiar: people exalt themselves against God and over others. Pride increases, arrogant and/or abusive behavior ensues, and people suffer. C.S. Lewis Institute