When Pandavas were in the forest, Krishna visited them. The brothers told Krishna that they took turns during nights to keep a vigil and control the activities of evil spirits and demons. Yuddhistra tried to dissuade Krishna from participating in sentry duty, but Krishna insisted. During the Lord’s turn, no evil spirit appeared. Then came Arjuna, and Krishna watched him from a distance. To Arjuna’s surprise, no evil spirit appeared while Krishna was there. Krishna later explained to Arjuna that evil spirits were only a reflection of one’s hatred and fear, and when one is free from these, no evil spirit would appear or do any harm. Krishna revealed that the Divine existed even in the so-called evil spirits and that if a person gets rid of the evil qualities within him, the evil spirits cannot do any harm. Your anger assumes the form of a demon. If you develop love, everything you confront will have the form of love.
— Bhagawan Sri Sathya Sai Baba (Divine Discourse, Jan 14, 1998)