The reason that fasting has an effect on the spirits of evil rests in its powerful effect on our own spirit. A body subdued by fasting brings the human spirit freedom, strength, sobriety, purity, and keen discernment.
What can God do with one who willfully gives himself over to the world, and is deceived by its pleasures, or led astray by material wanderings? The man to whom He gives help is the one who turns away from material pleasures and from his former habits, who drags his mind at all times to the Lord, whether it will or not, who denies himself and seeks the Lord only. This is the man whom He keeps under His care: who guards himself on every side from the snares and entanglements of the material world, who works out his own salvation with fear and trembling, who passes with all heed amidst the snares and entanglements and lusts of this world, and seeks the help of the Lord, and hopes by His mercy to be saved through grace.
The vain desires of this world separate us from our homeland; love of them and habit clothe our soul as if in a hideous garment. We, traveling on the journey of this life and calling on God to help us, ought to be divesting ourselves of this hideous garment and clothing ourselves in new desires, in a new love of the age to come, and thereby to receive knowledge of how near or how far we are from our heavenly homeland.
When walking in the way of righteousness, it is impossible not to meet with trouble, or that the body should not suffer pain and weakness and should remain immutable, if we want to live in virtue.
In the grim struggle with the invisible enemies of our salvation, the supreme weapon is the prayer of Jesus. `All the nations' - the vociferous and wily demons are called nations - `surround me,' says David, `and in the name of the Lord I repulsed them. They encircled and surrounded me like bees, and they burnt like fire among thorns; and in the name of the Lord I repulsed them' (Ps. 117:10-12). With the name of Jesus flog the foes, because there is no stronger weapon in heaven or earth.
Because the nous can get tired by the reciting of all the words of the Jesus Prayer, it is necessary to make it shorter: 'Lord Jesus Christ, have mercy on me.' Or, 'Lord have mercy on me.' Or, 'Lord Jesus.' As the Christian progresses in the work of the Jesus Prayer, he can decrease the words. He can even sometimes insist on the word 'Jesus,' which he says repeatedly (Jesus, Jesus, Jesus, my Jesus)--a wave of calmness and joy rises in him. He should remain in this sweetness which appears and not stop the prayer, even if his usual rule of prayer is finished. He should seize and keep this warmth of his heart and take advantage of this gift of God! For it is a great gift which God sends from on high. The warmth of the heart helps the nous effectively to be fixed on the words of the Jesus Prayer ... If one wants to spend all day in prayer, he should follow the recommendation of the Holy Fathers. He should pray for an hour, read for an hour and then again spend an hour in prayer. When he is engaged in manual work too, he should try to say the Jesus Prayer.
Many are the obstacles that stand in the way of pleasing God; for not merely poverty and obscurity but also riches and honor are trials for the soul. Indeed, to some extent even the solace and ease which grace bestows on the soul can easily become a temptation and a hindrance if the soul is not properly conscious of these effects of grace and does not enjoy them with great circumspection and understanding: for the spirit of evil tries to persuade the soul to relax now it possesses grace, and so contrives to implant in it sluggishness and apathy.
Knowing the exact nature of everything, God permits each person to be tested according to his strength. As St. Paul puts it: 'God is to be trusted not to let you be tried beyond your strength, but with the trial He will provide a way out, so that you are able to bear it' (1 Cor. 10:13).
Having guarded ourselves against distractions and worries, let us turn our attention to our body on which mental vigilance is completely dependent. Human bodies differ widely from one another in strength and health. Some by their strength are like copper and iron; others are frail like grass. For this reason everyone should rule his body with great prudence, after exploring his physical powers. For a strong and healthy body, special fasts and vigils are suitable; they make it lighter, and give the mind a special wakefulness. A weak body should be strengthened by food and sleep according to one's physical needs, but on no account to satiety. Satiety is extremely harmful even for a weak body; it weakens it, and makes it susceptible to disease. Wise temperance of the stomach is a door to all the virtues. Restrain the stomach, and you will enter Paradise. But if you please and pamper your stomach, you will hurl yourself over the precipice of bodily impurity, into the fire of wrath and fury, you will coarsen and darken your mind, and in this way you will ruin your powers of attention and self-control, your sobriety and vigilance…
The soul that really loves God and Christ, though it may do ten thousand righteousnesses, esteems itself as having wrought nothing, by reason of its insatiable aspiration after God. Though it should exhaust the body with fastings, with watchings, its attitude towards the virtues is as if it had not even begun to labor for them.
The head of every good striving and the pinnacle of all corrections is to persevere in prayer, by which we may ever obtain, through entreaty of God, all the other virtues as well. By prayer those who are worthy partake of the sanctity of God and spiritual activity and the union of the mind with the Lord in unutterable love. He who constantly forces himself to endure in prayer is roused by spiritual love to Divine fervor and flaming desire towards God, and he receives, according to his measure, the grace of spiritual, sanctifying perfection.
