In the war of the flesh, only turning our back saves us—that is, we must flee from fantasies and thoughts as soon as they appear. Do not linger at all in order to examine or to converse with fantasies! The imagination is a great and terrible snare; things avoided by the eyes and the touch are approached with the greatest of ease by the imagination.
Strive to keep your mind from imagining any worldly thing outside of your monastery. Only one thought should replace them all—the remembrance of the adored Jesus. If something in your cell reminds you of someone, you must necessarily get rid of it, to avert by all means any occasion for war. Make an effort to erase your past. When it rouses itself and tries to choke you, call on Jesus and He will be ready to help you.

Elder Ephraim of Arizona