The man who does not humble himself and does not cleanse his heart from evil desires fasts in vain. He may eat nothing at all, but it will be to no avail if there is evil inside him. He must first cleanse himself from the evil within in order to receive the Lord.
Even a pious person is not immune to spiritual sickness if he does not have a wise guide -- either a living person or a spiritual writer. This sickness is called prelest, or spiritual delusion, imagining oneself to be near to God and to the realm of the divine and supernatural. Even zealous ascetics in monasteries are sometimes subject to this delusion, but of course, laymen who are zealous in external struggles (podvigi) undergo it much more frequently. Surpassing their acquaintances in struggles of prayer and fasting, they imagine that they are seers of divine visions, or at least of dreams inspired by grace. In every event of their lives, they see special intentional directions from God or their guardian angel. And then they start imagining that they are God's elect, and often try to foretell the future. The Holy Fathers armed themselves against nothing so fiercely as against this sickness -- prelest.
For not only are spiritual riches and heavenly gifts received from God, but earthly and material possessions also proceed from His bounty, that He may be justified in requiring an account of those things which He has not so much put in our possession, as committed to our stewardship. God’s gifts, therefore, we must use properly and wisely, lest the material for good work should become an occasion for sin.
Among the virtues which must be instilled in a child's heart with special persistence, an important and fundamental place belongs to truthfulness, that is to say, a feeling of love for truth and an aversion towards falsehood. After obedience, this virtue should be given second place. If falsehood is the root of all sin, truth is the beginning and foundation for nearly all virtues, and for this reason parents must direct their attention primarily at nurturing truthfulness in children.
Abba Or used to say this, 'Do not speak in your heart against your brother like this: 'I am a man of more sober and austere life than he is,' but put yourself in subjection to the grace of Christ, in the spirit of poverty and genuine charity, or you will be overcome by the spirit of vainglory and lose all you have gained. For it is written in the Scriptures: 'Let him who stands take heed lest he fall.' (I Corinthians 10:12) Let your salvation be founded in the Lord.'
For forgiveness of sins is most efficaciously prayed for with almsgiving and fasting, and supplications that are winged by such aids mount swiftly to God’s ears; since it is written, 'the merciful man doeth good to his own soul' (Prov. xi. 17), and nothing is so much a man’s own as that which he spends on his neighbor. For that part of his material possessions with which he ministers to the needy, is transformed into eternal riches, and such wealth is begotten of this bountifulness as can never be diminished or in any way destroyed, for 'blessed are the merciful, for God shall have mercy on them' (Matt. v.7), and He himself shall be their chief Reward, who is the Model of His own command.
And among all the works of God, before which the mind grows faint with awe, which so rejoices yet overwhelms the soul as the Passion of our Savior? For as often as we dwell, as best we can, upon His Omnipotence, which He shares with the Father in one and the same nature, more wondrous does His lowliness seem to us than His power; and with more difficulty do we grasp His emptying Himself of the divine Majesty, than His sublime uplifting of the form of a servant.
The evil one cannot comprehend the joy we receive from the spiritual life; for this reason he is jealous of us, he envies us and sets traps for us, and we become grieved and fall. We must struggle, because without struggles we do not obtain virtues.
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 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.
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.
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.
Accordingly, a man will neither be puffed up through pride, nor cast down by despair, if he uses the good things divinely bestowed on him, to the glory of the Giver; withholding his desires from the things which he knows will hurt him. And so he that would preserve himself from the wickedness of envy, from the corruption of sensuality, from the unrest of anger, from the desire of revenge, will be purified by the sanctifying power of true abstinence, and will taste the joy of imperishable delights, so that by making spiritual use of them, he will learn to change earthly possessions into heavenly, not by storing what he has received, but by multiplying more and more that which he has been given.