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.
Our works in this life are the sowing, and the future life is the harvest of what we have sown. Whatever one sows here, that is what he shall reap there. If one hastens to cultivate the field of his heart, to fertilize it and to sow in it the seeds of immortal grain, he can confidently expect to see a corresponding harvest unto eternal rest and delight. He that sows with tears of repentance shall reap with rejoicing and 'shall be filled,' says the Prophet (Psalms 16:16 and 125:6), for sweet rest follows upon the labors of piety. But rest and refreshment are denied to him who has not labored in the work of piety-he that is idle should not eat, it is said (cf. II Thessalonians 3:10).
Disciplined piety feeds the soul on holy thoughts. What can be more blessed than to imitate on earth the chorus of the angels; to begin the opening day with prayer, honouring the Creator with hymns and songs; and when the sun is up to turn to work, always accompanied by prayer, and to season one's labours with singing? Cheerfulness and freedom from sorrow are the gifts which the soul received from the singing of hymns.
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.
And so it is a likeness of eternity, beginning as it does and ending, as in a circling course, at the same point. On this day the rules of the church have educated us to prefer the upright attitude of prayer, for by their plain reminder they, as it were, make our mind to dwell no longer in the present but in the future. Moreover every time we fall upon our knees and rise from off them we show by the very deed that by our sin we fell down to earth, and by the loving kindness of our Creator were called hack to heaven.
When we return to prayer after a period of reading we find a rejuvenated and invigorated soul, stirred by the desire for God. The best form of prayer is one that implants the clearest idea of God in the soul and thus makes space for the presence of God within us. We become a temple of God when our continuous meditation on Him is not constantly interrupted by ordinary worries, and the spirit is not disturbed by unexpected emotions. Thus, in flight from all things, the spirit who loves God can approach God who drives out everything that leads us to evil, and holds steadfastly to everything that leads to virtue.
If your heart has been softened either by repentance before God or by learning the boundless love of God towards you, do not be proud with those whose hearts are still hard. Remember how long your heart was hard and incorrigible. Seven brothers were ill in one hospital. One recovered from his illness and got up and rushed to serve his other brothers with brotherly love, to speed their recovery. Be like this brother. Consider all men to be your brothers, and sick brothers at that. And if you come to feel that God has given you better health than others, know that it is given through mercy, so in health you may serve your frailer brothers.
Be slow and dull to idle talk, but knowing and wise in hearkening to the saving words of the Holy Scriptures. Let the hearing of worldly tales be to you as a bitter taste in your mouth, but the discourse of holy men as a honeycomb (Prov. 16.24). Be eager to imitate men of disciplined habits and do not wait to be taught each thing. Strive to attain to the greater virtues, but do not neglect the lesser ones. Do not make light of a fall even if it be the most venial of faults; rather, be quick to repair it by repentance, although many others may commit a large number of faults, slight and grievous, and remain unrepentant. Judge not the sins of others, for they have a just Judge ‘Who will render every man according to his works’ (Rom. 2.6); but be master of what is your own and lighten your own burden insofar as you have the power, for he who increases his own burden will also carry it. In repentance is salvation, but folly is the death of repentance.
The power given by the Lord to His seventy disciples is given to all Christians (Mk. 16:17). Use it, Christian! With the name of Jesus cut off their heads, that is the first appearances of sin in our thoughts, fancies and feelings. Destroy within you the devil's rule over you; destroy all his influence over you; acquire spiritual freedom. The foundation for your struggle is the grace of holy baptism; your weapon is prayer in the name of Jesus.