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.
Those who have truly decided to serve the Lord God should practice the remembrance of God and uninterrupted prayer to Jesus Christ, mentally saying: Lord Jesus Christ, Son of God, have mercy on me, a sinner.
As therefore the Lord does nothing without the Father, for says He, 'I can of mine own self do nothing,' so do you, neither presbyter, nor deacon, nor layman, do anything without the bishop.
It is as necessary for a man to say the Jesus Prayer as it is for a ship in danger to send out steadily the S.O.S. signal: Lord Jesus Christ have mercy on me.
One time St. Nicodemos, on a feast day, was walking toward the Great Lavra (on Mt Athos). On his way he came across a kellion where he spent the night. At midnight he saw an elder and his accompanying monks entering the church. He secretly went in also, and there he saw the elder and his subordinate monks uttering the Jesus Prayer ('Lord Jesus Christ, Son of God, have mercy on me'), sometimes in a kneeling position, sometimes standing up. And at the time of the Holy Communion, he saw all their faces shining only a little less dimly than the sun.
During the time of one’s confession not only the person who makes his confession is judged, but the confessor as well. In the past, confessors were practical. They did not judge on the basis of the seriousness of a transgression, but rather on the intent. They did not concentrate so much on the sins being confessed as on thinking of how to treat the repentant person’s soul.
We should not miss any chance to us to say the Jesus Prayer. We must not let our mind wander in vain things. In saying the Jesus Prayer one's mind finds rest and joy. It is like small children who for the whole day run around, shouting and playing and hitting each other. But the one thing that gives them rest and great joy is when at night they find themselves in their mother's arms. This way also one's mind instead of being scattered about, out to be devoted to mental prayer.
The right practice of abstinence is needful not only to the mortification of the flesh but also to the purification of the mind. For the mind then only keeps holy and spiritual fast when it rejects the food of error and the poison of falsehood.
Fasting needn't be limited to abstinence from food alone, because true fasting is departure from evil deeds. Forgive your neighbor any insult, abstain from causing your neighbor offence, abstain from irritation, from senseless sorrows, from fear, wrath, and so on. ‘True fasting is alienation from evil, temperance of the tongue, setting aside of wrath, casting out of lust, idle talk, lies, and oath-breaking’…This is a true and pleasing fast for the Lord. Departing from these vices and from a corrupt state is what comprises a true fast.
The nature then of Christ's teaching is attested by His own holy statements: that they who wish to arrive at eternal blessedness may understand the steps of ascent to that high happiness. 'Blessed,' He saith, 'are the poor in spirit, for theirs is the kingdom of heaven.' It would perhaps be doubtful what poor He was speaking of, if in saying 'blessed are the poor' He had added nothing which would explain the sort of poor: and then that poverty by itself would appear sufficient to win the kingdom of heaven which many suffer from hard and heavy necessity. But when He says 'blessed are the poor in spirit,' He shows that the kingdom of heaven must be assigned to those who are recommended by the humility of their spirits rather than by the smallness of their means.
What guarantees a safe journey to eternity is effort, dignity, the sense of being unworthy before God, hope (the spiritual oxygen), consolation, and certainty. Not misery and compelled obedience and forced prayer; not tears and sadness - these all come from Satan. Yes, I ought to weep for my sins, but all the while hoping in God's love. But I cannot stand it if I cry because the devil wants me (to despair). Many times Satan crushes a person with despair and the devil becomes the victor. But this does not happen when one is like a child on his father's arm - trusting. Our trust in God is a ceaseless prayer that brings positive results. Despair comes from the devil. Don't say, 'Oh, what has happened to me?' but give yourself to God totally and hope in Him.
Apostolic teaching, Beloved, exhorts us that we put off the old man with his deeds (Eph. iv. 22; Col. iii. 9), and renew ourselves from day to day by a holy manner of life. For if we are the temple of God, and if the Holy Spirit is a Dweller in our souls, as the Apostle says: You are the temple of the living God (II Cor. vi. 16); we must then strive with all vigilance that the dwelling of our heart be not unworthy of so great a Guest.
When the enemy tempts you with thoughts of faithlessness, with all your heart say, I believe completely whatever the Church believes, whatever Christ says in the Holy Gospels, whatever the Holy Apostles and the Holy Fathers said. 'I don't, however, believe you, devil, for you are a liar and a thief.'