Join to every breath a sober invocation of the name of Jesus and the thought of death with humility. Both these practices bring great profit to the soul.
Brethren, let us also occupy yourselves with noetic prayer… and seeking God’s mercy, cry out with a humble heart from morning till night and if possible all night long, saying constantly: 'Lord Jesus Christ, Son of God, have mercy on us.'
Grace abides in us from the time of our holy baptism; but, through our inattention, vanity and the wrong life we lead it is stifled, or buried. When a man resolves to lead a righteous life and is zealous for salvation, the fruit of his whole labor is, therefore, the restoration in force of this gift of grace. It comes to pass in a two-fold manner: first, this gift becomes revealed through many labors in following the commandments; insofar as a man succeeds in following the commandments, this gift becomes more radiant and brilliant. Secondly, it manifests and reveals itself through constant invocation of the Lord Jesus in prayer. The first method is powerful, but the second is more so, so that even the first method gains power through it. Thus, if we sincerely wish to open the seed of grace concealed in us, let us hasten to train ourselves in this latter exercise of the heart, and let us have only this work of prayer in our heart, without forms, without images, till it warms our heart and makes it burn with ineffable love of the Lord.
The practice of the prayer of Jesus holy David, or more accurately the Holy Spirit by the mouth of David, offers to all Christians without exception: 'The kings of the earth and all people, princes and all judges of the earth, young men and maidens - let elders with the young praise the name of the Lord, for His name alone is exalted (PS. 148:11-13).' A literal understanding of the states enumerated here would be perfectly permissible, but their essential meaning is spiritual.
At your work, flee conversation; only measured words in case of need. The hands should work for the needs of the body, and the mind should say the sweetest name of Christ, so that the need of the soul, which we must not forget even for moment, also will be provided for.
The power given by the Lord to His seventy disciples is given to all Christians (Mk. 16:17). Use it, Christian! With the name of Jesus cut off their heads, that is the first appearances of sin in our thoughts, fancies and feelings. Destroy within you the devil's rule over you; destroy all his influence over you; acquire spiritual freedom. The foundation for your struggle is the grace of holy baptism; your weapon is prayer in the name of Jesus.
Prayer is the mind's dialogue with God, in which words of petition are uttered with the intellect riveted wholly on God. For when the mind unceasingly repeats the name of the Lord and the intellect gives its full attention to the invocation of the divine name, the light of the knowledge of God overshadows the entire soul like a luminous cloud.
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.
Whenever we are filled with evil thoughts, we should throw the invocation of our Lord Jesus Christ in their midst. Then, as experience has taught us, we shall see them instantly dispersed like smoke in air. Once the intellect is left to itself again, we can renew our constant attentiveness and our invocation. Whenever we are distracted, we should act in this way.
The incessant invocation of God's name is a medicine which mortifies not just the passions, but even their influence. Just as the physician puts medications or dressings on a wound that it might be healed, without the patient even knowing the manner of their operation, so also the name of God, when we invoke it, mortifies all passions, though we do not know how that happens.
What should one do so that the mind might be constantly occupied with God? If we do not acquire the three following virtues: love for God and men, continence, and the Prayer of Jesus, then our mind cannot be completely occupied with God. For love makes anger meek, continence weakens fleshly desire, and prayer draws the mind away from thoughts and banishes every hatred and high-mindedness.
The late Athonite Father Tikhon used to say: The prayer, 'Lord Jesus have mercy on us' is worth one hundred drachmas, but 'Glory to God' is word one thousand. Glorifying God is more valuable than anything else, because in the first instance, people often say the Jesus Prayer when needing something; but when one glorifies God in the midst of suffering, it is an ascesis.
'Lord Jesus Christ, Son of God, have mercy on me, a sinner.' Let your attention and instruction be centered on this. Walking, eating, standing in church before the beginning of the service, continue with the prayer; on entering and departing keep this prayer on your lips and within your heart. In such a manner, with the invocation of the Name of God you will find peace, you will attain to purity of spirit and body; and the Holy Spirit, the Origin of all good, will make for Himself a dwelling within you and will guide you in all piety and purity.
Just as it is impossible to cross the sea without a boat, so it is impossible to repulse the provocation of an evil thought without invoking Jesus Christ.
We should not miss any chance to us to say the Jesus Prayer. We must not let our mind wander in vain things. In saying the Jesus Prayer one's mind finds rest and joy. It is like small children who for the whole day run around, shouting and playing and hitting each other. But the one thing that gives them rest and great joy is when at night they find themselves in their mother's arms. This way also one's mind instead of being scattered about, out to be devoted to mental prayer.