Demons, Deliverance, and Discernment by Father Mike Driscoll

Spiritual Pride

The demons were good when God created them, but they fell from grace because of the sin of pride: "You said in your heart... ' I will ascend above the heights of the clouds, I will make myself like the Most High.' But you are brought down to Sheol, to the depths of the Pit" (Isa. 14:13-14). This illustrated the importance of being spiritually humble; we resist demons by avoiding the very vice that brought them down.

(Pg. 143)