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.
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.
Those pursuing the spiritual way should train themselves to hate all uncontrolled desires until this hatred becomes habitual. With regard to self-control in eating, we must never feel loathing for any kind of food, for to do so is abominable and utterly demonic. It is emphatically not because any kind of food is bad in itself that we refrain from it. But by not eating too much or too richly we can to some extent keep in check the excitable parts of our body. In addition we can give to the poor what remains over, for this is the mark of sincere love.
Fasting is an exceptional virtue; it represses bodily impulses and gives strength to the soul to fight against the poisoning of the heart through the senses, and provides it with a remedy against any past poisoning. Fasting causes the mind to be cleansed constantly. It withers up every evil thought and brings healthy, godly thoughts -- -holy thoughts that enlighten the mind and kindle it with more zeal and spiritual fervor.
Fasting is an ordinance of the Church, obliging the Christian to observe it on specific days. Concerning fasting, our Savior teaches: 'When thou fastest, anoint thine head, and wash thy face; that thou appear not unto men to fast, but unto thy Father Who is in secret: and thy Father, Who seeth in secret, shall reward thee openly.' From what the Savior teaches we learn (a) that fasting is pleasing to God, and (b) that he who fasts for the uplifting of his mind and heart towards God shall be rewarded by God, Who is a most liberal bestower of Divine gifts, for his devotion. In the New Testament fasting is recommended as a means of preparing the mind and the heart for divine worship, for long prayer, for rising from the earthly, and for spiritualization.
According to St. Gregory the Sinaite there are three degrees in eating: temperance, sufficiency, and satiety. Temperance is when someone wants to eat some more food but abstains, rising from the table still somewhat hungry. Sufficiency is when someone eats what is needed and sufficient for normal nourishment. Satiety is when someone eats more than enough and is more than satisfied. Now if you cannot keep the first two degrees and you proceed to the third, then, at least, do not become a glutton, remembering the words of the lord: 'Woe unto you that are full now, for you shall hunger' (Lk. 6:25). Remember also that rich man who ate in this present life sumptuously every day, but who was deprived of the desired bosom of Abraham in the next life, simply because of this sumptuous eating.
Do not hesitate to go late at night to those places where you usually feel afraid. But if you yield only a little to such weakness, then this childish and ridiculous infirmity will grow old with you. As you go on your way, arm yourself with prayer. When you reach the place, stretch out your hands. Flog your enemies with the name of Jesus, for there is no stronger weapon in heaven or earth. When you get rid of the disease of fear, praise Him who has delivered you. If you continue to be thankful, He will protect you for ever.
Fasting is beneficial when it is undertaken for quelling desire, humbling the soul, transforming hatred, extinguishing anger, erasing remembrance of wrongs, and for the purity of the understanding and the practice of prayer.
Fasting, while of value in itself, is not something to boast of in front of God, for it is simply a tool for training those who desire self-restraint. The ascetic should not feel proud because he fasts; no artist ever boasts that his accomplishment is simply due to his tools; but he waits for the work itself to give proof of his skill.
Have confidence in the compassion of our Creator. Reflect well on what you are now doing, and keep before you the things you have done. Lift up your eyes to the overflowing compassion of heaven, and while He waits for you, draw near in tears to our merciful Judge. Having before your mind that He is a Just Judge, do not take your sins lightly; and having also in mind that He is compassionate, do not despair. The God-Man gives man confidence before God.
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.
No satiety has brought forth prudent behavior; for it is in the nature of fire to consume matter. And a filled stomach expels refined thoughts; it is the tendency of opposites to oppose each other.
Once two brothers came to a certain old man. It was his custom not to eat every day but when he saw them he received them joyfully and said, 'A fast has its own reward, but he who eats for the sake of love fulfils two commandments: he leaves his own will and he refreshes his brothers.'
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.
