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.
'Then the devil left Him, and angels came and ministered to Him' (Matthew 4:11). It does not say that the angels were with our Lord during the actual time when He was being tempted. In the same way, when we are being tempted, God's angels for a time withdraw a little. Then, after the departure of those tempting us, they come and minister to us with divine intellections, giving us support, illumination, compunction, encouragement, patient endurance, joyfulness, and everything that saves and strengthens and renews our exhausted soul. As Nathaniel was told, 'You will see the angels ascending and descending upon the Son of man' (John 1:51); in other words, the ministry and assistance of the angels will be given generously to mankind.
Suppose you have ordered yourself not to eat fish; you will find that the enemy continually makes you long to eat it. You are filled with an uncontrollable desire for the thing that is forbidden. In this way you can see how Adam's fall typifies what happens to all of us. Because he was told not to eat from a particular tree, he felt irresistibly attracted to the one thing that was forbidden him.
The desire for possessions is dangerous and terrible, knowing no satiety; it drives the soul which it controls to the heights of evil. Therefore, let us drive it away vigorously from the beginning. For once it has become master it cannot be overcome.
Concerning the fault of our brother, seeing and hearing of it, be toward it as a blind man, deaf man, and dumb one, not seeing, not hearing, and not speaking, as one crude of mind, not understanding, not showing oneself to be wise. But to oneself be attentive, discerning, and clear-sighted.
Do not say...that one or two books is sufficient for instructing the soul. After all, even the bee collects honey not from one or two flowers only, but from many. Thus also he who reads the books of the Holy Fathers is instructed by one in faith or in right thinking, by another in silence and prayer, by another in obedience and humility and patience, by another in self-reproach and in love for God and neighbor; and, to speak briefly, from many books of the Holy Fathers a man is instructed in life according to the Gospel.
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).
The passion of self-esteem is a three-pronged barb heated and forged by the demons out of vanity, presumption and arrogance. Yet those who dwell under the protection of the God of heaven (cf. Ps. 91.1) detect it easily and shatter its prongs, for through their humility they rise above such vices and find repose in the tree of life.
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.
No one can be saved without the renunciation of his will, even though he might struggle fervently, for our will and our manner are like a bronze wall between us and God.
When anyone is disturbed or saddened under the pretext of a good and soul-profiting matter, and is angered against his neighbor, it is evident that this is not according to God: for everything that is of God is peaceful and useful and leads a man to humility and to judging himself.
One must clean the royal house from every impurity and adorn it with every beauty, then the king may enter into it. In a similar way one must cleanse the earth of the heart and uproot the weeds of sin and the passionate deeds and soften it with sorrows and the narrow way of life, sow in it the seed of virtue, water it with lamentation and tears, and only then does the fruit of dispassion and eternal life grow. For the Holy Spirit does not dwell in a man until he has been cleansed from passions of the soul and body. Only one thing may remain within a man, either the Holy Spirit or the passions. Where the Holy Spirit is, there the passions do not come near, and where the passions are, there the Holy Spirit does not dwell, but rather the evil one.
Remember, O my soul, the terrible and frightful wonder: that your Creator for your sake became Man, and deigned to suffer for the sake of your salvation. His angels tremble, the Cherubim are terrified, the Seraphim are in fear, and all the heavenly powers ceaselessly give praise; and you, unfortunate soul, remain in laziness. At least from this time forth arise and do not put off, my beloved soul, holy repentence, contrition of heart and penance for your sins.
Therefore, if you wish to conquer the passions, cut off the love of pleasure; but if you are pursuing food, you will spend a life in passions; the soul will not be humbled if the flesh is not deprived of bread. It is not possible to deliver the soul from perdition while protecting the body from unpleasantness.