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.
The undefiled beauty of fasting is the pure mother of character. It causes philosophy to gush forth, and offers a crown. It negotiates Paradise for us and grants a paternal family for those who fast. Of this Adam was deprived, and he attracted death, when he dishonored the worth of feasting. For at the time when it was treated scornfully, the God of all, the Creator and the Master was at once displeased. To those who honor it He grants eternal life.
Once two brethren came to a certain elder whose custom it was not to eat every day. But when he saw the brethren he invited them with joy to dine with him, saying: Fasting has its reward, but he who eats out of charity fulfills two commandments, for he sets aside his own will and he refreshes his hungry brethren.
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.
I shall speak first about control of the stomach, the opposite to gluttony, and about how to fast and what and how much to eat. I shall say nothing on my own account, but only what I have received from the Holy Fathers. They have not given us only a single rule for fasting or a single standard and measure for eating, because not everyone has the same strength; age, illness or delicacy of body create differences. But they have given us all a single goal: to avoid over-eating and the filling of our bellies... A clear rule for self-control handed down by the Fathers is this: stop eating while still hungry and do not continue until you are satisfied.
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.
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.
Fasting is absolutely indispensable for man. From the external aspect, it is a struggle of filial obedience to God, Who has given us the rules of fasting through His Holy Spirit. From the inner aspect, fasting is a struggle of restraint and self-limitation. In this lies the great value and sense of fasting, since a strict observance of fasts tempers one's will and perfects the character of one who is firm in his religious convictions and actions. Let us not forget that Christ Himself fasted, and foretold that His apostles would also fast.
Beware of limiting the good of fasting to mere abstinence from meats. Real fasting is alienation from evil. ‘Loose the bands of wickedness.’ For give your neighbor the mischief he has done you. Forgive him his trespasses against you. Do not ‘fast for strife and debate.’ You do not devour flesh, but you devour your brother. You abstain from wine, but you indulge in outrages. You wait for evening before you take food, but you spend the day in the law courts. Woe to those who are ‘drunken, but not with wine.’ Anger is the intoxication of the soul, and makes it out of its wits like wine.
And finally, did not the Lord Jesus Himself begin His divine ministry of the salvation of mankind with a long, forty day fast? And did not He, in this way, clearly show that we must make a serious beginning to our life as Christians with fasting? First, the fast, and then all the rest comes together with, and through, the fast. By His own example, the Lord showed us how great a weapon fasting is. With this weapon, He vanquished Satan in the wilderness, and with it was victorious over the three chief satanic passions with which Satan tempted Him: love of ease love of praise and love of money. These are three destructive greeds, the three greatest traps into which the evil enemy of the human race lures Christ's soldiers.
Let those of us who have wisely finished the course of fasting and who celebrate with love the beginning of the suffering of the Passion of the Lord, let us all, my brothers, zealously imitate the purity of self-controlled Joseph; let us fear the sterility of the fig tree; let us dry up through almsgiving the sweetness of passion. In order that we may joyously anticipate the Resurrection, let us procure like myrrh pardon from on high, because the eye that never sleeps observes all things.
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.
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.
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.
A righteous person who is wise resembles God: he never disciplines anyone in order to take vengeance upon a wrongdoing, but only so that the person may be set aright, or that others may be deterred.
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.
One should not ponder divine matters on a full stomach, say the ascetics. For the well-fed, even the most superficial secrets of the Trinity lie hidden.
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.