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.
Thus should we weep for the forgiveness of our sins. The words of the bearer of the purple should convince us of this: 'Going they went and wept, casting their seed; but coming they shall come with joyfulness, carrying their sheaves (Ps. 125:6);' as well as the words of St. Isaac the Syrian: 'Moisten your cheeks with the tears of your eyes, that the Holy Spirit may abide in you, and cleanse the filth of your malice. Move your lord with your tears, that He may help you' (homily 68).
One must by every means strive to preserve peace of soul and not be disturbed by offenses from others; for this one must in every way strive to restrain anger and by means of attentiveness to keep the mind and heart from improper feelings. And therefore we must bear offenses from others with equanimity and accustom ourselves to such a disposition of spirit that these offenses seem to concern not us, but others. Such a practice can give quietness to the human heart and make it as dwelling for God Himself.
Do not be ashamed to reveal your scabs to your spiritual director. Be prepared as well to accept from him disgrace for your sins, so that by being disgraced, you might avoid eternal shame.
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].
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.
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.
'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.
Watchfulness cleanses the conscience and makes it lucid. Thus cleansed, it immediately shines like a light that has been uncovered, banishing such darkness. Once this darkness has been banished through constant and genuine watchfulness, the conscience then reveals things hidden from us.
Let us go forward with the heart completely attentive and the soul fully conscious. For if attentiveness and prayer are daily joined together, they become like Elias' fire-bearing chariot, raising us to heaven. What do I mean? A spiritual heaven, with sun, moon and stars, is formed in the blessed heart of one who has reach a state of watchfulness, or who strives to attain it.
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.
Just as our Lord is solicitous about our salvation, so too the murderer of men, the devil, strives to lead a man into despair... Judas the betrayer was fainthearted and unskilled in battle, and so the enemy, seeing his despair, attacked him and forced him to hang himself; but Peter, a firm rock, when he fell into great sin, like one skilled in battle did not despair nor lose heart, but shed bitter tears from a burning heart, and the enemy, seeing these tears, his eyes scorched as by fire, fled far from him wailing in pain.
God's all-saving will consists in doing good solely to acquire the Holy Spirit, as an eternal, inexhaustible treasure which cannot be rightly valued... This is the oil in the lamps of the wise virgins which could burn long and brightly, and these virgins with their burning lamps were able to meet the Bridegroom Who came at midnight, and could enter the bridechamber of joy with Him. But the foolish ones, though they went to market to buy some oil when they saw their lamps going out, were unable to return in time, for the door was already shut. The market is our life; the door of the bridechamber which was shut and which barred the way to the Bridegroom is human death; the wise and foolish virgins are Christian souls; the oil is not good deeds but the grace of the All-Holy Spirit of God which is obtained through them and which changes souls from one state to another - that is, from corruption to incorruption, from spiritual death to spiritual life, from darkness to light, from the stable of our being (where the passions are tied up like dumb animals and wild beasts) into a temple of the Divinity, into the shining bridechamber of eternal joy in Christ Jesus our Lord, the Creator and Redeemer and eternal Bridegroom of our souls.
A single word made the thief pure and holy, despite all his previous crimes, and brought him into paradise (cf. Luke 23:42-43). A single ill-advised word prevented Moses from entering the promised land (cf. Num. 20:12). We should not suppose, then, that garrulity is only a minor disease. Lovers of slander and gossip shut themselves out of the kingdom of heaven.
Sin, to one who loves God, is nothing other than an arrow from the enemy in battle. The true Christian is a warrior fighting his way through the regiments of the unseen enemy to his heavenly homeland.