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.
Concerning the fault of our brother, seeing and hearing of it, be toward it as a blind man, deaf man, and dumb one, not seeing, not hearing, and not speaking, as one crude of mind, not understanding, not showing oneself to be wise. But to oneself be attentive, discerning, and clear-sighted.
He who believes in Christ is not judged, for he judges himself, and sets his feet aright to follow the light that goes before him. As a man in deep darkness adapts his step to the candle in his hand, so also he who believes in Christ; that is, he who is set to follow after Christ as the light in the darkness of life.
Watch constantly, learning to understand God's law, for this warms the heart with heavenly fire. Guard your lips from the idle word, or empty talk, lest the heart gets used to evil words.
If a man only theorises about God, then he is helpless, utterly helpless, when confronted by an evil spirit. An evil spirit laughs at feeble worldly theorising. But as soon as a man begins to fast and to pray to God, the evil spirit becomes filled with inexpressible fear.
If you wish to be delivered from shameful passions, do not behave with anyone familiarly, especially with those toward whom your heart is inclined by a lustful passion; through this you will be delivered also from vainglory. For in vainglory is involved the pleasing of men, in the pleasing of men is involved familiarity of behavior, and familiarity of behavior is the mother of all passions.
If the humbling of oneself before men is needful that one might be exalted before God, and temporal toil is the prerequisite of immortal life, what does it matter if some shake their heads and laugh at your self-abasement?
A truly intelligent man has only one care -- wholeheartedly to obey Almighty God and to please Him. The one and only thing he teaches his soul is how best to do things agreeable to God, thanking Him for His merciful Providence in whatever may happen in his life. For just as it would be unseemly not to thank physicians for curing our body, even when they give us bitter and unpleasant remedies, so too would it be to remain ungrateful to God for things that appear to us painful, failing to understand that everything happens through His Providence for our good. In this understanding and this faith in God lie salvation and peace of soul.
My children, desire to purify your hearts from envy and from anger with each other, lest death should overcome you, and you will be counted among the murderers. For whosoever hates his brother, kills a soul.
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).
In the heart is the will; in the heart is love; in the heart is the mind--in the heart is the image of the divine Trinity. The heart is the home of the Father, the altar of the Son and the workshop of the Holy Spirit. God wants our hearts: Son, give Me thy heart. Oh, my brother, above and beyond all else that you keep safe, guard your heart. Let the mountains be overthrown and the seas dried up; let friends forsake you and riches betray you; let your body be eaten by worms; let the world pour on you all the scorn of which it is capable--and do not fear. Only guard your heart; guard it and make it cleave to the Lord; give it into His keeping. Life flows from the heart; but whence comes this life in the heart, unless it is the abode of the breath of the Lord and Source of life-God? Oh, my brother, the Spirit of God Himself can, when He so desires, dwell in the human heart. He not only can, but wills to do so. Only, He waits for you to prepare your heart for Him; to make it into a temple, for God the Holy Spirit only lives in a temple. As a snake protects its head, so, my son, guard your heart. For the life that comes from the living God enters into it and flows forth from it.
What is self-justification? - Self-justification is when a man denies his sin, as we see in the case of Adam, Eve, Cain and others who have sinned but, wishing to justify themselves, denied their sin.