It is as necessary for a man to say the Jesus Prayer as it is for a ship in danger to send out steadily the S.O.S. signal: Lord Jesus Christ have mercy on me.
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.
The heart which is constantly guarded, and is not allowed to receive the forms, images and fantasies of the dark and evil spirits, is conditioned by nature to give birth from within itself to thoughts filled with light. For just as coal engenders a flame, or a flame lights a candle, so will God, who from our baptism dwells in our heart, kindle our mind to contemplation when He finds it free from the winds of evil and protected by the guarding of the intellect.
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.
Fear God and keep His commandments both in your feelings and in your intellect. If you force yourself to keep them in your intellect, bit by bit you will attain to fulfilling them in your feelings.
We should zealously cultivate watchfulness, my brethren; and when, our mind purified in Christ Jesus, we are exalted by the vision it confers, we should review our sins and our former life, so that shattered and humbled at the thought of them we may never lose the help of Jesus Christ our God in the invisible battle.
And pray ye without ceasing in behalf of other men. For there is in them hope of repentance that they may attain to God. See, then, that they be instructed by your works, if in no other way. Be ye meek in response to their wrath, humble in opposition to their boasting: to their blasphemies return your prayers; in contrast to their error, be ye steadfast in the faith; and for their cruelty, manifest your gentleness. While we take care not to imitate their conduct, let us be found their brethren in all true kindness; and let us seek to be followers of the Lord (who ever more unjustly treated, more destitute, more condemned? ), that so no plant of the devil may be found in you, but ye may remainin all holiness and sobriety in Jesus Christ, both with respect to the flesh and spirit.
A man is neither saved nor lost by the place he is in, but is saved or lost by his deeds. Neither a holy place nor a holy state is of use to him who does not fulfill the commandments of the Lord.
The lower you descend, the higher you ascend; and when, like the psalmist, you regard yourself as nothing before the Lord (cf. Ps. 39:5), then imperceptibly you will grow great. And when you begin to realize that you have nothing and know nothing, then you will become rich in the Lord through the practice of the virtues and spiritual knowledge.
The sun rising over the earth creates the daylight; and the venerable and holy name of the Lord Jesus, shining continually in the mind, gives birth to countless intellections radiant as the sun.
One time St. Nicodemos, on a feast day, was walking toward the Great Lavra (on Mt Athos). On his way he came across a kellion where he spent the night. At midnight he saw an elder and his accompanying monks entering the church. He secretly went in also, and there he saw the elder and his subordinate monks uttering the Jesus Prayer ('Lord Jesus Christ, Son of God, have mercy on me'), sometimes in a kneeling position, sometimes standing up. And at the time of the Holy Communion, he saw all their faces shining only a little less dimly than the sun.
One of the Fathers said: just as it is impossible for a man to see his face in troubled water, so too the soul, unless it be cleansed of alien thoughts, cannot pray to God in contemplation.