For this world is opposed to the world above, and this present age to the eternity above. The Christian therefore, according to Holy Scripture, must deny the world, and be translated and pass in mind out of this present age, in which the mind is placed and exposed to allurements ever since the transgression of Adam, into another age, and in frame of thought must live in the world of the Godhead above, as it is said, But our conversation is in heaven. (Phil. iii. 20.).
Many are the obstacles that stand in the way of pleasing God; for not merely poverty and obscurity but also riches and honor are trials for the soul. Indeed, to some extent even the solace and ease which grace bestows on the soul can easily become a temptation and a hindrance if the soul is not properly conscious of these effects of grace and does not enjoy them with great circumspection and understanding: for the spirit of evil tries to persuade the soul to relax now it possesses grace, and so contrives to implant in it sluggishness and apathy.
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.
The soul that really loves God and Christ, though it may do ten thousand righteousnesses, esteems itself as having wrought nothing, by reason of its insatiable aspiration after God. Though it should exhaust the body with fastings, with watchings, its attitude towards the virtues is as if it had not even begun to labor for them.
If you wish to be saved and 'to come unto the knowledge of the truth' (I Tim. 2:4), endeavor always to transcend sensible things, and through hope alone to cleave to God. Then you will find principalities and powers fighting against you (Eph. 6:12), deflecting you against your will and provoking you to sin. But if you prevail over them through prayer and maintain your hope, you will receive God's grace, and this will deliver you...
The most important thing in any good effort and the height of all activities is to persevere in prayer, by means of which we can always acquire through supplication the other virtues from God as well.
There is a sin which is always 'unto death' [1 Jn 5:16]; the sin which we have not repented. Even a saint's prayers will not be heard for the unrepented sin. The person who repents correctly does not imagine that his sins are cancelled through his own effort; but knows that through this effort he makes peace with God.
Also in another place it shows that the angels are the ministers of the saints. For when Elijah was on the mountain and foreigners were rising up against him, his servant said, 'Many are coming against us and we are all alone.' Then Elijah answered, 'Do you not see the armies and multitudes of angels with us surrounding us to aid us?' (2 Kg. 6:15). You see how the Master and the multitude of angels are standing by the side of their servants.
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.
My son, says Scripture, if you come to serve the Lord, prepare your soul for trial, set you heart straight, and patiently endure (Eccles. 2:1-2). And elsewhere it is said: Accept everything that comes as good, knowing that nothing occurs without God willing it. Thus the soul that wishes to do God's will must strive above all to acquire patient endurance and hope. For one of the tricks of the devil is to make us listless at times of affliction, so that we give up our hope in the Lord. God never allows a soul that hopes in Him to be so oppressed by trials that it is put to utter confusion. As St. Paul writes: God is to be trusted not to let us be tried beyond our strength, but with the trial He will provide a way out, so that we are able to bear it (I Cor. 10:13). The devil harasses the soul not as much as he wants but as much as God allows him to. Men know what burden may be placed on a mule, what on a donkey, and what on a camel, and load each beast accordingly; and the potter knows how long he must leave the pots in the fire, so that they are not cracked by staying in it too long or rendered useless by being taken out of it before they are properly fired. If human understanding extends this far, must not God be much more aware, infinitely more aware, of the degree of trial it is right to impose on each soul, so that it become tried and true, fit for the kingdom of heaven?
Knowing the exact nature of everything, God permits each person to be tested according to his strength. As St. Paul puts it: 'God is to be trusted not to let you be tried beyond your strength, but with the trial He will provide a way out, so that you are able to bear it' (1 Cor. 10:13).