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.'
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.
When tested by some trial you should try to find out not why or through whom it came, but only how to endure it gratefully, without distress or rancor.
If you wish to be saved and 'to come unto the knowledge of the truth' (I Tim. 2:4), endeavor always to transcend sensible things, and through hope alone to cleave to God. Then you will find principalities and powers fighting against you (Eph. 6:12), deflecting you against your will and provoking you to sin. But if you prevail over them through prayer and maintain your hope, you will receive God's grace, and this will deliver you...
If a man has some spiritual gift and feels compassion for those who do not have it, he preserves the gift because of his compassion. But a boastful man will lose it through succumbing to the temptations of boastfulness.
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...
He is not yet a faithful servant who bases himself on bare knowledge alone; a faithful servant is he who professes his faith by obedience to Christ, Who gave the commandments.
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.
One of the Fathers said: just as it is impossible for a man to see his face in troubled water, so too the soul, unless it be cleansed of alien thoughts, cannot pray to God in contemplation.
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.