Definition of Sobriety from the Desert Father Hesychius of Jerusalem

Sobriety is the steadfast setting up of the thought of the mind and posting it at the door of the heart, so that it sees alien thoughts as they come, those thieves and robbers, and hears what these destroyers say and do; and sees what is the image inscribed and figured in them by the demons, who are trying thus to seduce the mind by fantasy. For this work, when it is done with loving effort, reveals to us very fundamentally and clearly, by experience, the art of mental war and brings skill in it.