Spiritual delusion (Gk. plani; Slav, prelest) is the condition which results from succumbing to a spiritual deceit of the evil-one, or from spiritual self-deceit. It is a state that may be attained by those who do not “contend lawfully” in the contest of spiritual warfare. It can befall an individual or a whole group of people.
St Gregory of Sinai warns against spiritual delusion in the Philokalia, and the twentieth century Church father, Metropolitan Antony (Khrapovitsky) of blessed memory, describes mass spiritual delusion to priests concerning holy confession:
“Weak faith and carelessness are expressions of irreligiousness in people. But 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 spiritual delusion, or 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 struggle undergo it much more frequently. Surpassing their acquaintances in spiritual 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 — spiritual delusion.
“Spiritual delusion endangers a man’s soul if it lurks in him alone; but it is dangerous and imperiling also for the whole of local church life; if society is seized in its grasp, if it makes its appearance anywhere as a spiritual epidemic and the life of a whole…” group of people becomes… “oriented entirely towards it. “
The words of Metropolitan Antony further illustrate our own era very well:
“…anyone can pass himself off as a prophet, provided that he is not lazy, or ashamed to do so. No matter how much people are disappointed by his predictions, they will not cease believing in his special knowledge, but will explain the failure of the prophecy by their own lack of understanding. But the false prophets of Christ will have honour, glory and every possible gift heaped upon them as before. Everyone knows how destructive are the consequences of being carried away by this ‘khlystism‘; it begins with struggles of prayer and fasting, and ends with shameless dissolution and unimaginable sexual depravity.”
Not all examples of mass spiritual delusion end up in depravity; some maintain very high examples of external morality. But Satan uses them to rob people of their salvation in other ways, as in the deceptive Ecumenist Movement, which appears so laudable on the surface, but which in fact is eroding faith and sound doctrine in every direction. The aim of spiritual delusion is to destroy the soul of one person, or of a whole group of people. Disobedience to the holy Church and her canons is the surest sign of mass spiritual delusion and false teachers.
—The Spiritual Meadow (Introduction)