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.
At first it may appear very difficult to you, but be assured, as it were from Almighty God, that this very name of our Lord Jesus Christ, constantly invoked by you, will help you to overcome all difficulties, and in the course of time you will become used to this practice and will taste how sweet is the name of the Lord. Then you will learn by experience that this practice is not impossible and not difficult, but both possible and easy. This is why St. Paul, who knew better than we the great good which such prayer would bring, commanded us to pray without ceasing. He would not have imposed this obligation upon us if it were extremely difficult and impossible, for he knew beforehand that in such case, having no possibility of fulfilling it, we would inevitably prove to be disobedient and would transgress his commandment, thus incurring blame and condemnation. The Apostle could have had no such intention.
No virtue makes flesh-bound man so like a spiritual angel as does self-restraint, for it enables those still living on earth to become, as the Apostle says, 'citizens of heaven' (cf. Phil. 3:20).
It is, indeed, impossible for the mind not to be troubled by thoughts, but accepting them or rejecting them is possible for everyone who makes an effort...therefore we practice the frequent reading of Scripture, so that we may be open to a spiritual point of view. For this reason we frequently chant the psalms, so that we may continually grow in compunction. For this reason we are diligent in vigils, fasting, and praying, so that the mind which has been stretched to its limits may not taste earthly things but contemplate heavenly ones. When these things cease because negligence has crept in again, then, it is inevitable that the mind, by the accumulated filth of the vices, will soon turn in a carnal direction and fall.
Grace comes immediately to meet some of those who strive, giving them assurance of the earnest of their inheritance, (Eph. 1:14), letting them taste the promised prizes, as if stretching out a loving hand to welcome them and anointing them for further struggles. With others, however, grace waits for the end of the struggle, and prepares for them the crown of patience as well. As one of the God-bearing Fathers says, 'some receive holy rewards before their labors, some during their labors, and some when they depart.'
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.
That prayer may be poured forth with that fervor and singleness of heart that it ought to have, these rules must always be observed. In the first place, anxiety concerning the things of the flesh must be altogether be put away; then we must not allow to enter our minds any thought or even memory of worldly cares or business. We must cut off slanderings, vain words or many words, jestings and the like. We must root out the disturbances of anger especially, and despondency, and also tear up the
evil roots of carnal lust and avarice. And so with these and similar faults done entirely away with and cut off, - things which can also be discerned by human eyes - and with such a cleansing and purifying as we have mentioned first carried out in the sincerity of simplicity and innocence, we must lay the unshakable foundations of humility strong enough to sustain a tower which shall pierce the heavens.
Sometimes, when we are overcome by pride or impatience and are unwilling to amend our ill-conditioned and disordered way of life, we complain that what we need is solitude, as though in solitude, meeting with no provocation, we should find there the virtue of patience, making excuses for our slackness, and laying the blame of our agitation not upon our own lack of patience, but ascribing it to the faults of our brethren, whereas so long as we impute to others the causes of our own faults, we shall never be able to reach the goal of patience and of perfection.
Of the Only Case in Which Anger is Good... But we have a use for anger most properly planted within us, and for this use alone it is profitable and healthful for us to entertain it, namely, when we burn with wrathful indignation against the lustful motions of our own hearts, and are enraged to find that those things which we should be ashamed to do or to speak of before men have found admittance into the secret places of our minds. We may then well dread and fear exceedingly the presence of the Angels and the Omnipresence of God Himself, and His all-seeing Eye from which no secrets of our hearts can lie hid.
A man may seem to be silent, but if his heart is condemning others, he is babbling ceaselessly. But there may be another who talks from morning till night and yet he is truly silent, that is, he says nothing that is not profitable.
Let us make ourselves the dwelling of peace, sanctification, and contrite prayer, without which no one will see God (Heb. 12:14). Let us long with the full assurance of faith for that vision promised to the pure in heart, and may we do everything to attain it, for it is accompanied by eternal life, unfading goodness, inexhaustible riches, unchanging and unending delight, glory and kingdom.
Blessed are the pure in heart, for they shall see God. Everything we do, our every objective, must be undertaken for the sake of this purity of heart. This is why we take on loneliness, fasting, vigils, work, nakedness. For this we must practice the reading of the Scripture, together with all the other virtuous activities, and we do so to trap and to hold our hearts free of the harm of every dangerous passion and in order to rise step by step to the high point of love.
The closet of the soul is the body; our doors are the five bodily senses. The soul enters its closet when the mind does not wander hither and thither, roaming among things and affairs of the world, but stays within, in our heart. Our senses become closed and remain closed when we do not let them be attached to external sensory things, and in this way our mind remains free from every worldly attachment, and by secret mental prayer unites with God its Father. 'And thy Father which seeth in secret shall reward thee openly,' adds the Lord. God who knows all secret things sees mental prayer and rewards it openly with great gifts. For that prayer is true and perfect which fills the soul with Divine grace and spiritual gifts.