They say that God allows the demons to make war on us for five reasons: the first, they say is so that we may distinguish between virtue and vice by making war and being warred against; secondly, so that we may acquire virtue by warfare and toil, and possess it sure and steadfast; thirdly, so that we may not think highly of ourselves when we make progress in virtue, but may learn to be humble; fourthly, so that we may completely hate vice, after we have experienced it; and finally, apart from of these, the fifth reason is so that we may not forget our frailty or the power of God which helped us to attain passionlessness.
~Saint Maximos the Confessor
