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.
It is impossible for the soul to be liberated from turbulent thoughts without the virtue of non-possessiveness. And without peace of the bodily senses it is impossible for the soul to have a peaceful intellect. And if it does not come into temptations it will not acquire wisdom of the Holy Spirit. And without laborious and persistence in reading, it will not come to the discernment of thoughts. And without the stillness of thoughts, the intellect cannot move to seek the hidden mysteries of God.
To many people the Saints seem far from us. But the Saints are far only from those who have taken themselves away from them, and are very close to those who keep Christ’s commandments and possess the grace of the Holy Spirit.
You know that evil entered into us through the transgression of the commandments. Hence it is obvious that by keeping them, evil departs from us. But without the doing of the commandments we should not even aspire or hope for purity of soul, because at the very outset we do not walk on the path that leads us to purity of soul. Do not say that God can give us the grace of purity of soul even without our keeping the commandments.
Obedience is necessary not only for monks, but for all people. Even the Lord was obedient. Proud and self-assured do not let grace reside within them, and therefore they never have internal peace, whereas the soul of the obedient easily accepts the grace of the Holy Spirit, bringing with it joy and serenity.
Where there is pride there cannot be grace, and if we lose grace we also lose both love of God and assurance in prayer. The soul is then tormented by evil thoughts and does not understand that she must humble herself and love her enemies, for there is no other way to please God.
As it is not possible to cross over the great ocean without a ship, so no one can attain to love without fear. This filthy sea, which lies between us and the paradise of the heart, we may cross by the boat of repentance, whose oarsmen are those of fear. But if fear's oarsmen do not pilot the boat of repentance whereby we cross over the sea of this world to God, we shall be drowned in the sordid abyss.
Do not be surprised that when you draw near to virtue, grievous and intense tribulations come to you on all sides: for virtue is not considered virtue, if it does not involve hard work.
If you will pray for your enemies, peace will come to you; but when you can love your enemies - know that a great measure of the grace of God dwells in you, though I do not say perfect grace as yet, but sufficient for salvation. Whereas if you revile your enemies, it means there is an evil spirit living in you and bringing evil thoughts into your heart, for, in the words of the Lord, out of the heart proceed evil thoughts - or good thoughts.