Some fast, live as solitaries without possessions, and pray that God will curb their nature; yet in spite of this, they allow themselves to slander, to reproach and judge their neighbors and ridicule them - and so the Divine help departs from them. They are left to themselves and are unable to find strength needed to counteract our nature's sinful suggestions. In a certain cenobitic monastery, there lived a hermit whose name was Timothy. One of the brethren in the cenobium became subject to temptation. When the abbot heard about this, he asked Timothy how the fallen brother should be treated. The hermit advised him that the seduced one should be expelled. And when they had sent him away, the fallen brother's temptation fell upon Timothy, so that he was in peril. Timothy began tearfully to groan for help and mercy from God. A voice came to him, 'Timothy, know that I have sent this temptation to you, because you disdained your brother in his hour of temptation.' One must deal with the members of Christ - Christians - with great care and circumspection. One must actually suffer with them in their weakness, cutting off only those who show no hope for restored health, lest they infect others with their ailments.
He who has not received within himself the kingdom of God cannot recognize the Antichrist. He is absolutely sure to become in a way incomprehensible to himself his follower.
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.
One should nourish the soul with the word of God: for the word of God, as St. Gregory the Theologian says, is angelic bread, by which are nourished souls who hunger for God. Most of all, one should occupy oneself with reading the New Testament and the Psalter, which one should do standing up. From this there occurs an enlightenment in the mind, which is in the mind, which is changed by a Divine change.
When walking in the way of righteousness, it is impossible not to meet with trouble, or that the body should not suffer pain and weakness and should remain immutable, if we want to live in virtue.
We must accomplish the course of our earthly pilgrimage with the greatest attention and watchfulness over ourselves, unceasingly calling upon God in prayer for help.