Even a pious person is not immune to spiritual sickness if he does not have a wise guide -- either a living person or a spiritual writer. This sickness is called prelest, or spiritual delusion, imagining oneself to be near to God and to the realm of the divine and supernatural. Even zealous ascetics in monasteries are sometimes subject to this delusion, but of course, laymen who are zealous in external struggles (podvigi) undergo it much more frequently. Surpassing their acquaintances in struggles of prayer and fasting, they imagine that they are seers of divine visions, or at least of dreams inspired by grace. In every event of their lives, they see special intentional directions from God or their guardian angel. And then they start imagining that they are God's elect, and often try to foretell the future. The Holy Fathers armed themselves against nothing so fiercely as against this sickness -- prelest.
If the passions strike you from time to time, this should not distress you. We must continue the 'unseen warfare' all our lives. The battle itself is not a problem; there is trouble only if we become weak in it. If this does not happen, our spiritual life is in good order. The peace that is with you in battle bears witness to this. But we must beware that we do not feel a different kind of peace, the kind one feels when there is no battle. This kind of peace is dangerous. It indicates that the enemy has done away with open battle and wants to build an invisible and clever snare for us! In cases like this one must intensify one's usual vigilance and sobriety! Do not weaken in any way!
In so much as you sincerely compel yourself to do God's commandments, an understanding of the infirmity of your being will be born in you, and in as much as you have this understanding, one of the basic Christian virtues, humility, will in turn be born. God's grace is given only for humility, not for works, although humility is engendered by works. This is the law of true asceticism.
