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.
A sorrowless earthly life is a true sign that the Lord has turned his face from a man, and that he is displeasing to God, even though outwardly he may seem reverent and virtuous.
There is nothing more efficacious against the wiles of the devil, dearly beloved, than the kindness of forgiveness, and the bountifulness in charity, by means of which sin is either avoided or overcome.
Apostolic teaching, Beloved, exhorts us that we put off the old man with his deeds (Eph. iv. 22; Col. iii. 9), and renew ourselves from day to day by a holy manner of life. For if we are the temple of God, and if the Holy Spirit is a Dweller in our souls, as the Apostle says: You are the temple of the living God (II Cor. vi. 16); we must then strive with all vigilance that the dwelling of our heart be not unworthy of so great a Guest.
The adversary will sit in the temple of Jerusalem, in order to show himself as Christ, he will demand that those who are captivated by him should worship him as Christ. The Antichrist will demand worship as if he were God.
In this order, and by this succession, the ecclesiastical tradition from the apostles, and the preaching of the truth, have come down to us. And this is most abundant proof that there is one and the same vivifying faith, which has been preserved in the Church from the apostles until now, and handed down in truth.
We must accomplish the course of our earthly pilgrimage with the greatest attention and watchfulness over ourselves, unceasingly calling upon God in prayer for help.
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).
The right practice of abstinence is needful not only to the mortification of the flesh but also to the purification of the mind. For the mind then only keeps holy and spiritual fast when it rejects the food of error and the poison of falsehood.
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 grim struggle with the invisible enemies of our salvation, the supreme weapon is the prayer of Jesus. `All the nations' - the vociferous and wily demons are called nations - `surround me,' says David, `and in the name of the Lord I repulsed them. They encircled and surrounded me like bees, and they burnt like fire among thorns; and in the name of the Lord I repulsed them' (Ps. 117:10-12). With the name of Jesus flog the foes, because there is no stronger weapon in heaven or earth.
As the earth, long awaiting moistening and at last receiving it in abundance, suddenly is covered by tender and bright greenery, so also the heart, exhausted by dryness, and afterwards revived by tears, emits from itself a multitude of spiritual thoughts and feelings, adorned by the common flower of humility. The labor of weeping, being inseparable from the labor of prayer, requires the same conditions for success as prayer requires. Prayer needs patient, constant dwelling in itself; weeping requires the same. Prayer needs wearying of the body, and brings about exhaustion of the body; this exhaustion produces weeping, which must be born in the troubling and wearying of the body.
For by prayer we obtain the divine favor, by fasting we extinguish the concupiscences of the flesh, by almsgiving sins are redeemed (Dan. iv. 24); and by all three together, the image of God is renewed in us, provided that we are ever ready in His praise, eager without ceasing for our own purification, and disposed at all times to assist our neighbor.
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.