Every tribulation reveals the state of our will, whether it inclines to the right or to the left. An unexpected tribulation is called temptation, because it subjects a man to a test of his secret dispositions.
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.
The Lord commands all men to repent (Matt. 4:17), so that even the spiritual and those making progress should not neglect this injunction and fail to give attention to the smallest and most subtle errors.
This prayer should never be absent from you: 'Lord Jesus Christ, Son and Logos of the living God, through the Theotokos and all the Saints, have mercy upon me, Thy sinful and unworthy servant.' (This is the actual Jesus Prayer: 'O LORD JESUS CHRIST, SON OF GOD, HAVE MERCY UPON ME, A SINNER.') Always say this prayer both with your mouth and with your mind, day and night, wherever you may be, whether eating, walking, working, or sitting. Always meditate on it, as it benefits you a great deal, frees you here from every evil, delivers you there from eternal Hell, and renders you worthy of going to Paradise, our heavenly country.
If you want cure your soul, you need four things. The first is to forgive your enemies. The second is to confess thoroughly. The third is to blame yourself. The fourth is to resolve to sin no more. If we wish to be saved, we must always blame ourselves and not attribute our wrong acts to others. And God, Who is most compassionate, will forgive us.
When the first order of angels fell from the angelic glory and became demons, the other nine orders humbled themselves and worshipped the All-holy Trinity, and remained in their place and rejoice forever. We, too, my brethren, must reflect what an evil thing pride is - that it cast down the devil from angelic glory and he will always burn in Hell - and that humility kept the angels in Heaven, and they rejoice perpetually in the glory of the Holy Trinity. Let us then, my brethren, avoid pride, because it is the first daughter of the devil, is a path that leads to Hell; and let us have humility, because it is angelic—it is a path that leads to Paradise.
He who chooses maltreatment and dishonor for the sake of truth is walking on the apostolic path; he has taken up the cross and is bound in chains (cf. Mt 16:24). But when he tries to concentrate his attention on the heart without accepting these two, his intellect wanders from the path and he falls into the temptations and snares of the devil.
The abstinent withdraws from gluttony, the uncovetous from covetousness, the silent from wordiness, the pure from attachment to sensory pleasures, the chaste from fornication, he who is content with what he has from love of money, the meek from agitation (anger), the humble from vanity, the obedient from objection, he who is honest with himself from hypocrisy; equally, he who prays withdraws from despair, the willing pauper from acquisitiveness, he who professes his faith from denying it, the martyr from idolatry – so you see that each virtue, performed even unto death, is nothing but withdrawal from sin; and withdrawal from sin is a natural action, not an action which could be rewarded by the kingdom.
He who reveres the Lord does what is commanded, and if he commits some sin or disobeys Him, endures whatever he has to suffer for this as being his desert.
A brother who shared a lodging with other brothers asked Abba Bessarion, 'What should I do?' The old man replied, 'Keep silence and do not compare yourself with others.'
Those who have sinned must not despair. Let that never be. For we are condemned not for the multitude of evils, but because we do not want to repent...