There is a difference, Dearly Beloved Brethren, between the delights of the body and those of the soul, that the delights of the body, when we do not possess them, awaken in us a great desire for them; but when we possess them and enjoy them to the full they straightway awaken in us a feeling of aversion. But spiritual delights work in the opposite way. While we do not possess them we regard them with dislike and aversion; but once we partake of them we begin to desire them, and the more do we hunger for them. In one case the appetite pleases, the reality brings displeasure; in the other it is the appetite [that] displeases, the reality delights us more and more. In the one case appetite leads to fullness, and fullness to disgust; in the other appetite begets fullness, and fullness in turn begets appetite. For spiritual delights, when they fill the soul, increase in us a desire of them; and the more we savor them, the more do we come to know what we should eagerly love.
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.
Fasting was of no benefit to that Pharisee in the Gospel, even though he always fasted two days a week, because he had adulterated it with pride and condemnation of his neighbor (Luke 18:11-12). Not that this means fasting is unprofitable. Moses, Elijah & the Lord Himself showed how beneficial it is for those who fast properly in a way pleasing to God.
People have to answer greatly for not keeping the rules of the Church with respect to the fasts. People justify themselves by saying that they never considered it a sin to eat dairy products during the fasts. They repent and consider themselves sinners in every other respect, but they do not think to repent about not keeping the fasts. Meanwhile, they are transgressing the commandment of our holy Mother, the Church, and according to the teaching of the Apostle Paul, they are as the heathen and publicans because of their disobedience.
Fasting needn't be limited to abstinence from food alone, because true fasting is departure from evil deeds. Forgive your neighbor any insult, abstain from causing your neighbor offence, abstain from irritation, from senseless sorrows, from fear, wrath, and so on. ‘True fasting is alienation from evil, temperance of the tongue, setting aside of wrath, casting out of lust, idle talk, lies, and oath-breaking’…This is a true and pleasing fast for the Lord. Departing from these vices and from a corrupt state is what comprises a true fast.
Fasting is the champion of every virtue, the beginning of the struggle, the crown of the abstinent, the beauty of virginity and sanctity, the resplendence of chastity, the commencement of the path of Christianity, the mother of prayer, the well-spring of sobriety and prudence, the teacher of stillness, and the precursor of all good works. Just as the enjoyment of light is coupled with healthy eyes, so desire for prayer accompanies fasting that is practiced with discernment.
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).
In preparing for battle, however, do not think that you will always be victorious. Often there will be only hardship that will bring nothing but affliction... Provide yourself with only one thing, strong courage: no matter what happens, stay with what you have begun... No matter how life goes, whatever successes and failures there are, you should give all of this over to God's will.
We are told: It is no big deal to eat non-Lenten food during Lent. It is no big deal if you wear expensive beautiful outfits, go to the theater, to parties, to masquerade balls, use beautiful expensive china, furniture, expensive carriages and dashing steeds, amass and hoard things, etc. Yet what is it that turns our heart away from God, away from the Fountain of Life? Because of what do we lose eternal life? Is it not because of gluttony, of expensive clothing like that of the rich man of the Gospel story, is it not because of theaters and masquerades? What turns us hard-hearted toward the poor and even toward our relatives? Is it not our passion for sweets, for satisfying the belly in general, for clothing, for expensive dishes, furniture, carriages, for money and other things? Is it possible to serve God and mammon, to be a friend to the world and a friend to God, to serve Christ and Belial? That is impossible. Why did Adam and Eve lose paradise, why did they fall into sin and death? Was it not because of one evil? Let us attentively consider why we do not care about the salvation of our soul, which cost the Son of God so dearly. Why do we compound sin upon sin, fall endlessly into opposing to God, into a life of vanity? Is it not because of a passion for earthly things and especially for earthly pleasures? What makes our hearts become crude? Why do we become flesh and not spirit, perverting our moral nature? Is it not because of a passion for food, drink, and other earthly comforts? How after this can one say that it does not matter whether you eat non-Lenten food during Lent? The fact that we talk this way is in fact pride, idle thought, disobedience, refusal to submit to God, and separation from Him.
The body is a slave, the soul a sovereign, and therefore it is due to Divine mercy when the body is worn out by illness: for thereby the passions are weakened, and a man comes to himself; indeed, bodily illness itself is sometimes caused by the passions.
Fasting appears gloomy until one steps into its arena. But begin and you will see what light it brings after darkness, what freedom from bonds, what release after a burdensome life…
To what end do fasting and penitence lead? For what purpose is this trouble taken? They lead to the cleansing of the soul from sins, to peace of heart, to union with God; they fill us with devotion and sonship, and give us boldness before God.
The man who does not humble himself and does not cleanse his heart from evil desires fasts in vain. He may eat nothing at all, but it will be to no avail if there is evil inside him. He must first cleanse himself from the evil within in order to receive the Lord.
Courage does not consist in defeating and oppressing one's neighbor, for this is overbearingness, which oversteps the bounds of courage. Nor again does it consist in fleeing terrified from the trials that come as a result of practicing the virtues; for this is cowardice and falls short of courage. Courage itself consists in persisting in every good work and in overcoming the passions of soul and body. For our struggle is not against flesh and blood, that is, against men, as was the case with the Jews of old, where to conquer other nations was to do the work of God; it is against principalities and powers, that is, against the unseen demons (Ephesians 6:12). He who is victorious conquers spiritually; otherwise he is conquered by the passions. The warfare described in the Old Testament prefigures our spiritual warfare. These two passions of overbearingness and cowardice, though they appear to be opposites, are both caused by weakness. Overbearingness pulls one upwards and is outwardly something startling and frightening, like some powerless bear, while cowardice flees like a chased dog. No one who suffers from either of these two passions puts his trust in the Lord, and therefore he cannot stand firm in battle, whether he is overbearing or cowardly. But the righteous man is as bold as a lion (Proverbs 28:1) in Christ Jesus our Lord, to whom be glory and dominion throughout the ages.
If a king wanted to take possession of his enemy's city, he would begin by cutting off the water and the food and so his enemies, dying of hunger, would submit to him. It is the same with the passions of the flesh; if a man goes about fasting and hungry the enemies of his soul grow weak.
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.