A proud soul is the slave of fear ( St. John of the Ladder )

Whoever has become a servant of the Lord fears only his Master. But whoever is without the fear of God is often afraid of his own shadow. Fearfulness is the daughter of unbelief. A proud soul is the slave of fear; hoping in itself, in comes to such a state that it is startled by a small noise, and is afraid of the dark. 

(St. John of the Ladder, The Ladder, 21.11,1,4)