As wax cannot take the imprint of a seal unless it is warmed or softened thoroughly, so a man cannot receive the seal of God's holiness unless he is tested by labors and weaknesses. That is why the Lord says to St. Paul: 'My grace is sufficient for you: for My power comes to its fullness in your weakness'; and the Apostle himself proudly declares: 'Most gladly therefore will I rather glory in my weaknesses, so that the power of Christ may rest upon me' (2 Cor. 12:9).
Let us have recourse to humility on all occasions; for the humble lie prone on the ground, and how can a man fall if he lies on the ground? But a man who stands on a height can easily fall.
Remember, O my soul, the terrible and frightful wonder: that your Creator for your sake became Man, and deigned to suffer for the sake of your salvation. His angels tremble, the Cherubim are terrified, the Seraphim are in fear, and all the heavenly powers ceaselessly give praise; and you, unfortunate soul, remain in laziness. At least from this time forth arise and do not put off, my beloved soul, holy repentence, contrition of heart and penance for your sins.
Condemn only yourself, and you will not be condemned at His second and awful coming. From your whole heart remit the sins of whoever sins before you, and your Father who is in heaven will remit your sins.
Leave off all evasions, bend your neck to humility and obedience, and you will receive mercy. If you practice with humility and obedience what you hear from the fathers, God will grant you His blessed help not only in the work you are doing, but will make all your works successful, for He protects the path of those who fear Him and watches their progress.
Acquire humility, which scorches the demons, obedience, which opens the door for the Son of God to enter a man, faith which saves a man, hope which makes him unashamed; and love which lets not a man fall away from God.
No one can be saved without the renunciation of his will, even though he might struggle fervently, for our will and our manner are like a bronze wall between us and God.
When we fervently remember God, we feel divine longing well up within us from the depths of our heart. The evil spirits invade and lurk in the bodily senses, acting through the compliancy of the flesh upon those still immature in soul. According to the Apostle, our intellect always delights in the laws of the Spirit (cf. Rom. 7:22), while the organs of the flesh allow themselves to be seduced by enticing pleasures. Furthermore, in those who are advancing in spiritual knowledge, grace brings an ineffable joy to their body through the perceptive faculty of the intellect. But the demons capture the soul by violence through the bodily senses, especially when they find us faint-hearted in pursuing the spiritual path. They are, indeed, murderers provoking the soul to what it does not want.
When you intend to do something and see that your thought is perturbed, and if after invoking God's Name it remains perturbed even by a hair's breadth, know from this that the action you mean to commit is from the evil one and refrain from commiting it. For nothing done with perturbation is pleasing to God.
To those who are just beginning to long for holiness, the path of virtue seems very rough and forbidding. It appears like this, not because it really is difficult, but because our human nature from the womb is accustomed to the wide roads of sensual pleasure. But those who have traveled more than half its length find the path of virtue smooth and easy. For when a bad habit has been subjected to a good one through the energy of grace it is destroyed along with the remembrance of mindless pleasures; and thereafter the soul gladly journeys on all the ways of virtue. At the beginning of the struggle, therefore, the holy commandments of God must be fulfilled with a certain forcefulness of will (cf. Matt. 11:12); then the Lord, seeing our intention and labor, will grant us readiness of will and gladness in obeying His purpose. For 'it is the Lord who makes ready the will' (Prov. 8:35, LXX), so that we always do what is right joyfully. Then shall we truly feel that 'it is God who energizes in you both the willing and the doing of His purpose' (Phil. 2:13).
Fasting, while of value in itself, is not something to boast of in front of God, for it is simply a tool for training those who desire self-restraint. The ascetic should not feel proud because he fasts; no artist ever boasts that his accomplishment is simply due to his tools; but he waits for the work itself to give proof of his skill.
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.
Those who meditate unceasingly upon the holy and glorious name [of Jesus] in the depths of their heart can sometimes see the radiance of their own spirit-intelligence. For when the mind is profoundly concentrated on this invocation, we feel experientially how it starts burning off all the layers of dirt that normally suffocates the soul.