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.
Do not be always wanting everything to turn out as you think it should, but rather as God pleases; then you will be undisturbed and thankful in your prayer.
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.
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.
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.
Go, sell all that belongs to you and give it to the poor and taking up the cross, deny yourself; in this way you will be able to pray without distraction.
A mind from which the thought of God has been carried away and which has thus become far removed from remembering Him, is also indifferent to sin with the outer senses. For such a mind can guide neither the hearing nor the tongue, since zest to work on itself has gone out of it.
Rivalry over material possessions has made us forget the counsel of the Lord, who urged us to take no thought for earthly things, but to seek only the kingdom of heaven (cf. Matt. 6:33).
Go, sell all that belongs to you and give it to the poor and taking up the cross, deny yourself; in this way you will be able to pray without distraction.
It is not always possible to fulfill the usual rules; one must take circumstances into account and try to fulfill what they make possible, as far as one can. The demons themselves are not unmindful of this law. So, being in constant enmity with us, they prevent us from doing what is possible and urge us to do what is impossible.