Peter was first given the keys, but then he was allowed to fall into the sin of denying Christ; and so his pride was humbled by his fall. Do not be surprised, then, if after receiving the keys of spiritual knowledge you fall into various evil thoughts. Glorify our Lord, for He alone is wise: through setbacks of this kind He restrains the presumption that we tend to feel because of our advance in the knowledge of God. Trials and temptations are the reins whereby God in His providence restrains our human arrogance.
Keep your mind from malicious thoughts of your neighbors, knowing that such thoughts are hurled by diabolical power, to keep your mind from your own sins and from seeking.
Labor to acquire meekness. Concerning the heavenly virtues, meekness and humility, the Lord Himself teaches us, saying: Learn of Me, for I am meek and humble in heart; and ye shall find rest unto your souls (Matt. 11:29). Learn not from angels, nor from men, but from Me, He says; that is, from the higher wisdom.
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].
A great effort and much toil are needed in prayer before we can reach a state in which our mind is no longer troubled, and so attain the inward heaven of the heart where Christ dwells. As St. Paul says, 'Do you not realize that Christ dwells within you, unless you are worthless?' (cf. 2 Cor. 13:5).
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.
Let him judge of another’s sin who has not on his conscience that which condemns himself. Let him judge who does not himself do what he judges must be punished in another; lest while judging the other he passes sentence upon himself. Let him give judgment on another’s sin who is not led to deliver it by any hate, by dislike, or foolish levity.
He who knows himself pays no heed to the sins of others, but looks at his own and is always repenting over them; he reflects concerning himself, and condemns himself, and does not interfere in anything apart from his own position.
Practice self-observation. And if you want to benefit yourself and your fellow men, look at your own faults and not those of others. The Lord tells us: 'Judge not, that ye be not judged,' condemn not that ye be not condemned. And the Apostle Paul says: 'Who art thou that judgest another man's servant?'
Fire makes iron impossible to touch, and likewise frequent prayer renders the intellect more forceful in its warfare with the enemy. That is why the demons strive with all their strength to make us slothful in attentiveness to prayer, for they know that prayer is the intellect's invincible weapon against them.
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.
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.'
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.
The humility which in due time and by God's grace, after many struggles and tears, is given by heaven to those who seek it is something incompararably stronger and higher than the sense of abasement felt by those who have lapsed from holiness. This higher humility is granted only to those who have attained true perfection and are no longer under the sway of sin.
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?