St. Praisios the Athonite, the Prayer Rope

-Elder, I'm not used to carrying the prayer rope.
-You should carry the prayer rope, so that you might not forget the prayer, which should work internally, within the heart. When of course you exit your cell, you should remember that the enemy is ready to fight you. Thus, imitate the good soldier, who exits the barracks always with his automatic weapon “at hand”. The prayer rope has a great power, and is the weapon of the monk, and its knots are bullets, which [when fired at the feet of the demons] make their sandals dance.

St. Paisios the Athonite “On Prayer”, Words VII.