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.
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.
Those who have acquired genuine prayer experience an ineffable poverty of the spirit when they stand before the Lord, glorify and praise Him, confess to Him, or present to Him their entreaties. They feel as if they had turned to nothing, as if they did not exist. That is natural. For when he who is in prayer experiences the fullness of the divine presence, of Life Itself, of Life abundant and unfathomable, then his own life strikes him as a tiny drop in comparison to the boundless ocean. That is what the righteous and long-suffering Job felt as he attained the height of spiritual perfection. He felt himself to be dust and ashes; he felt that he was melting and vanishing as does snow when struck by the sun's burning rays (Job 42:6).
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.
The way to attain compunction is an attentive life. ‘The beginning of repentance comes from the fear of God and attention,’ as the holy martyr Boniface says.
By holy baptism original sin is expunged, as also sins committed before baptism. It also eliminates the violent power sin has over us till rebirth; it gives us the grace of the Holy Spirit by which we are united with God in Christ, and we receive power to subdue and conquer sin. For the simple reason that we are not delivered from the struggle with sin, we cannot be entirely free from sin during the whole of our earthly life, and even the righteous man may fall seven times (i.e. often) and rise again by repentance, says Scripture (Prov. 24:16). He falls on account of his weakness and limitations, because he does not always notice sin which subtly and imperceptibly rears its head from his fallen nature, and which is artfully and imperceptibly offered and suggested by fallen spirits. Repentance becomes his secure possession, his constant weapon, his invaluable treasure. By repentance the righteous man maintains his fellowship with Christ. He is healed by repentance from the wounds caused by sin.
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…
In the evening, on going to sleep (an image of death for the life of that day); examine your actions during the day that has passed. Such an examination is not difficult for one who leads an attentive life, because attention destroys that forgetfulness which is so characteristic of a distracted person. And thus, recalling all your sins in deed, word, thought and feeling, offer repentance over them to God with the disposition and heartfelt promise of correction.
Sear your loins by abstaining from food, and prove your heart by controlling your speech, and you will succeed in bringing the desiring and incensive powers of your soul into the service of what is noble and good.
