Keep the eyes of your soul wide open; guard your senses, both those of the body (primarily the eyes ) as well as those of the soul (especially by keeping the mind from wandering ).
This is necessary because it is through these senses that all the poisonous germs of spiritual diseases creep in. and thus, in time, the careless Christian contracts many diseases and loses the invaluable health of his immortal soul.
Adultery of the soul occurs very easily when we allow filthy thoughts with their corresponding fantasies within us to overcome us.
My child, be careful with your eyes if you want to conquer the demon of lust. Likewise, it is no less dangerous to look at indecent images, newspapers, magazines, etc.
Elder Ephraim of Arizona
Counsels from the Holy Mountain
Chapter Fifteen.
On Prayer and Watchfulness.