The Holy Fathers teach us how to become familiar with the Gospel, how to read it and how to understand it, what helps and what opposes its understanding. Therefore, at first you must devote more time to reading the Holy Fathers...
The reason that fasting has an effect on the spirits of evil rests in its powerful effect on our own spirit. A body subdued by fasting brings the human spirit freedom, strength, sobriety, purity, and keen discernment.
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.
Faith is an eye that enlightens every conscience, and imparts understanding; for the Prophet saith, And if ye believe not, ye shall not understand (Is. vii, 9).
As the earth, long awaiting moistening and at last receiving it in abundance, suddenly is covered by tender and bright greenery, so also the heart, exhausted by dryness, and afterwards revived by tears, emits from itself a multitude of spiritual thoughts and feelings, adorned by the common flower of humility. The labor of weeping, being inseparable from the labor of prayer, requires the same conditions for success as prayer requires. Prayer needs patient, constant dwelling in itself; weeping requires the same. Prayer needs wearying of the body, and brings about exhaustion of the body; this exhaustion produces weeping, which must be born in the troubling and wearying of the body.
Nothing is more unsettling than talkativeness and more pernicious than an unbridled tongue, disruptive as it is of the soul’s proper state. For the soul’s chatter destroys what we build each day and scatters what we have laboriously gathered together.
For the complete fulfillment of its [the intellect's] purpose we should give it nothing but the prayer 'Lord Jesus'...Those who meditate unceasingly upon this glorious and holy name in the depths of their heart can sometimes see the light of their own intellect. For when the mind is closely concentrated upon this name, then we grow fully conscious that the name is burning up all filth which covers the surface of the soul; for it is written: 'our God is a consuming fire' (Deut. 4:24). Then the Lord awakens in the soul a great love for His glory...This is the pearl of great price which a man can acquire by selling all that he has, and so experience the inexpressible joy of making it his own.
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.
Watchfulness cleanses the conscience and makes it lucid. Thus cleansed, it immediately shines like a light that has been uncovered, banishing such darkness. Once this darkness has been banished through constant and genuine watchfulness, the conscience then reveals things hidden from us.
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).
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 receive from Heaven the gift of patience, be attentive and vigilant over yourself, so as to hold and keep within yourself the grace of God, lest sin should creep unnoticed into your soul or body and drive away this grace.
Some fast, live as solitaries without possessions, and pray that God will curb their nature; yet in spite of this, they allow themselves to slander, to reproach and judge their neighbors and ridicule them - and so the Divine help departs from them. They are left to themselves and are unable to find strength needed to counteract our nature's sinful suggestions. In a certain cenobitic monastery, there lived a hermit whose name was Timothy. One of the brethren in the cenobium became subject to temptation. When the abbot heard about this, he asked Timothy how the fallen brother should be treated. The hermit advised him that the seduced one should be expelled. And when they had sent him away, the fallen brother's temptation fell upon Timothy, so that he was in peril. Timothy began tearfully to groan for help and mercy from God. A voice came to him, 'Timothy, know that I have sent this temptation to you, because you disdained your brother in his hour of temptation.' One must deal with the members of Christ - Christians - with great care and circumspection. One must actually suffer with them in their weakness, cutting off only those who show no hope for restored health, lest they infect others with their ailments.
When walking in the way of righteousness, it is impossible not to meet with trouble, or that the body should not suffer pain and weakness and should remain immutable, if we want to live in virtue.