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 you want cure your soul, you need four things. The first is to forgive your enemies. The second is to confess thoroughly. The third is to blame yourself. The fourth is to resolve to sin no more. If we wish to be saved, we must always blame ourselves and not attribute our wrong acts to others. And God, Who is most compassionate, will forgive us.
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.
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.
This prayer should never be absent from you: 'Lord Jesus Christ, Son and Logos of the living God, through the Theotokos and all the Saints, have mercy upon me, Thy sinful and unworthy servant.' (This is the actual Jesus Prayer: 'O LORD JESUS CHRIST, SON OF GOD, HAVE MERCY UPON ME, A SINNER.') Always say this prayer both with your mouth and with your mind, day and night, wherever you may be, whether eating, walking, working, or sitting. Always meditate on it, as it benefits you a great deal, frees you here from every evil, delivers you there from eternal Hell, and renders you worthy of going to Paradise, our heavenly country.
When the attention of the mind is fixed in the heart it is possible to control what happens in the heart, and the battle against the passions assumes a rational character. The enemy is recognized and can be driven off by the power of the Name of Christ.
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.
But when the Holy Spirit dwells in the heart of a person, He shows him all his inner poverty and weakness, and the corruption of his heart and soul, and his separation from God; and with all his virtues and righteousness. He shows him his sins, his sloth and indifference regarding the salvation and good of people his self-seeking in his apparently most disinterested virtues, his coarse selfishness even where he does not suspect it. To be brief, the Holy Spirit shows him everything as it really is. Then a person begins to have true humility, begins to lose hope in his own powers and virtues, regards himself as the worst of men. And when a person humbles himself before Jesus Christ Who alone is Holy in the glory of God the Father, he begins to repent truly, and resolves never again to sin but to live more carefully. And if he really has some virtues, then he sees clearly that he practiced and practices them only with the help of God, and therefore he begins to put his trust only in God.
It is more serious to lose hope than to sin. The traitor Judas was a defeatist, inexperienced in spiritual warfare; as a result he was reduced to despair by the enemy's onslaught, and he went and hanged himself. Peter, on the other hand, was a firm rock: although brought down by a terrible fall, yet because of his experience in spiritual warfare he was not broken by despair, but leaping up he shed bitter tears from a contrite and humiliated heart. And as soon as our enemy saw them, he recoiled as if his eyes had been burnt by searing flames, and he took flight...
Jesus Christ said that the Holy Spirit blows where it wills and you hear the sound of it, but cannot tell where it comes from and where it goes (Jn. 3:8). This means that a person cannot force the Holy Spirit to come to him or predict the time when He may decide to do so. You can only feel His touch when this happens. Indeed, the book of Acts states that when the Holy Apostles and other Christians received the gifts of the Holy Spirit, it was always unexpectedly. He seldom descends immediately on those beseeching Him but does so when it suits Him, as God, to do so. No one should attempt to foretell when or what gifts, if any, he will receive or to consider himself worthy of His descent! The Grace of the Holy Spirit is a gift of His endless mercy. And gifts by definition are given when it suits the giver, and only those deemed suitable by the giver.
'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.
Some people when praised for their virtue are delighted, and attribute this pleasurable feeling of self-esteem to grace. Others when reproved for their sins are pained, and they mistake this beneficial pain for the action of sin.
He who chooses maltreatment and dishonor for the sake of truth is walking on the apostolic path; he has taken up the cross and is bound in chains (cf. Mt 16:24). But when he tries to concentrate his attention on the heart without accepting these two, his intellect wanders from the path and he falls into the temptations and snares of the devil.