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.
Beware of the counsels of the evil one, if he should come in the guise of one professing truth to beguile you and lead you into deceit. Even if he should come to you as an angel of light, do not believe him or obey him: for he is apt to fascinate the faithful by the attractive semblance of truth.
Let us then not be ashamed to confess our sins unto the Lord. Shame indeed there is when each makes known his sins, but that shame, as it were, ploughs his land, removes the ever-recurring brambles, prunes and thorns, and gives life to the fruits which he believed were dead. Follow him who, by diligently ploughing his field, sought for eternal fruit: 'Being reviled we bless, being persecuted we endure, being defamed we entreat, we are made as the offscouring of the world' (Luke 13:7). If you plough after this fashion you will sow spiritual seed. Plough that you may get rid of sin and gain fruit. He ploughed so as to destroy in himself the last tendency to persecution. What more could Christ give to lead us on to the pursuit of perfection, than to convert and then give us for a teacher one who was a persecutor?
It is more serious to lose hope than to sin. The traitor Judas was a defeatist, inexperienced in spiritual warfare; as a result he was reduced to despair by the enemy's onslaught, and he went and hanged himself. Peter, on the other hand, was a firm rock: although brought down by a terrible fall, yet because of his experience in spiritual warfare he was not broken by despair, but leaping up he shed bitter tears from a contrite and humiliated heart. And as soon as our enemy saw them, he recoiled as if his eyes had been burnt by searing flames, and he took flight...
What should one do so that the mind might be constantly occupied with God? If we do not acquire the three following virtues: love for God and men, continence, and the Prayer of Jesus, then our mind cannot be completely occupied with God. For love makes anger meek, continence weakens fleshly desire, and prayer draws the mind away from thoughts and banishes every hatred and high-mindedness.
If anyone thinks that he has love but does not have the same love for all, but distinguishes between persons, separating the lowly from the rich, the infirm from the healthy, a sinner from a righteous man, one far off from one near, one who is an enemy from one who loves you, such love is not perfect, but partial. Actual and perfect love consists in considering everyone and loving them equally, both those who love you and those who hate you. Such love, with which mercy is inseparable, is, in brief, a net for all virtues. It embraces and contains all the commandments of God within itself.
But there is hardly anything more serious than to be joined in marriage to a stranger (i.e., to an unbeliever), where the instigations both of lustful appetite and of disharmony and the shameful crimes of sacrilege are welded together. For if marriage itself needs to be sanctified by the priestly veil and blessing, how is it possible to speak of a marriage where there is no agreement in faith?
If the base of a felled tree that has grown old in the earth and rock ‘will bud at the scent of water . . . like a young plant’ (Job 14:9), it is also possible for us to be awakened by the power of the Holy Spirit and to flower with the incorruptibility that is ours by nature, bearing fruit like a young plant, even though we have fallen into sin.
Do all in your power not to fall, for the strong athlete should not fall. But if you do fall, get up again at once and continue the contest. Even if you fall a thousand times because of the withdrawal of God's grace, rise up again each time, and keep on doing this until the day of your death. For it is written, 'If a righteous man falls down seven times' - that is, repeatedly throughout his life - 'seven times shall he rise again' [Prov. 24:16].
Observe at the same time that the mystery consists in the very office of humility, for Christ says: 'If I, your Lord and Master, have washed your feet; how much more ought you to wash one another's feet.' For, since the Author of Salvation Himself redeemed us through His obedience, how much more ought we His servants to offer the service of our humility and obedience.
He stands, then - but not alone, for before Him go angels, saying: 'Lift up the gates, O ye the princes.' What gates? Even those of which the Psalmist sings in another place also: 'Open to me the gates of righteousness.' Open, then, thy gates to Christ, that He may come into thee - open the gates of righteousness, the gates of chastity, the gates of courage and wisdom. Believe the message of the angels: 'Be ye lifted up, ye everlasting doors, and the King of Glory shall come in, the Lord of Sabaoth.'