Conferences of St. John Cassian - Conference Eight on Principalities Part II

The group picked up with Abba Serenus' exposition of the nature and characteristics of demons - the fact that they occupy the airy void between heaven and earth, their hideous appearance, their mutual adversity (which is the result of their having befriended mutually opposed nations on earth), their titles, functions and hierarchy, and their assignment to individual human beings, such that each human being has a personal demon as well as a personal angel.  It is fortunate that human beings cannot ordinarily see them, for otherwise they would either be horrified by their aspect or seek to imitate them in their wickedness.  Finally , as aggressive as demons may be against humans, they may also obey them in one of two instances, either when rendered submissive by human holiness or when soothed by the sacrifices and incantations of the wicked.