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.
Train yourself to cut off an intrusive thought immediately…Be at pains over this, so that you acquire the habit. The soul is a creature of habit: according to the habit you have acquired, so will you act all the rest of your life.
If some Christians cannot comprehend our Orthodox faith, its Sacraments, it proves that the minds and hearts of such persons are too impure and passionate to bear its purity and brightness, just as sick eyes cannot bear the light of the sun. This heavenly treasure can only be comprehended by the hearts of those who free their minds and feelings from worldly attachments.
If you are enclosed within yourself through prayer, humility, and mourning, you will find a spiritual treasure -- only let pride and criticism be far from you.
If you possess the gift of mourning, hold on to it with all your might. For it is easily lost when it is not firmly established. And just as wax melts in the presence of fire, so it is easily dissolved by noise and bodily cares, and by luxury, and especially by talkativeness and levity.
Mourning according to God is sadness of soul and the disposition of a sorrowing heart, which ever madly seeks that for which it thirsts; and when it fails in its quest, it painfully pursues it, and follows in its wake grievously lamenting. Or thus: mourning is a golden spur in a soul which is stripped of all attachment and of all ties, fixed in a soul which is stripped of all attachment and of all ties, fixed by holy sorrow to watch over the heart.
Mourning has a twofold action: like water tears extinguish all the fire of passions and wash the soul clean of their foulness; and, again, through the presence of the Holy Spirit, it is like fire bringing life, warming the heart, and inciting it to love and desire God.
I am a Christian, you say, and content yourself with this. This is the first deceit - transferring to yourself the privileges and promise of Christianity, without any care to root true Christianity into yourself; or to ascribe to yourself that which can only be acquired by your strength and inner worthiness. Explain to yourself that it is illusory to hope in a name, that God can raise a son of Abraham from a stone and can take away your promise at any time if the conditions for participating in them are not soon fulfilled. Mainly, clarify to yourself what it means to be a Christian, unite yourself to this ideal, and you will see just how stable is this buttress to your blindness.
The first divine fruit of silence is mourning -- grief according to God -- joy-grief. Afterward come luminous thoughts, which bring the holy flow of tears streaming with life, from which also comes the second baptism and the soul is purified and shines and becomes like the angels.
The Christian ought not to be of doubtful mind, nor by anything drawn away from the recollection of God and of His purposes and judgments. The Christian ought in all things to become superior to the righteousness existing under the law, and neither swear nor lie. The Christian ought to be patient, whatever he has to suffer, and to convict the wrong-doer in season, not with the desire of his own vindication, but of his brother's reformation, according to the commandment of the Lord.
Those who mourn and those who are insensitive are not subject to fear, but the cowardly often have become deranged. And this is natural. For the Lord rightly forsakes the proud that the rest of us may learn not to be puffed up.
I consider those fallen mourners more blessed than those who have not fallen and are not mourning over themselves; because as a result of their fall, they have risen by a sure resurrection.
The designation of a Christian consists in glorifying the Heavenly Father by one's life. Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven (Matt. 5:16). But true glorification of God is possible only if one rightly believes and expresses his right belief in words and deeds.
As the gradual pouring of water on a fire completely extinguishes the flame, so the tears of mourning are able to quench every flame of anger and irritability. Therefore, we place this next in order. (after mourning).