Observe your thoughts, and beware of what you have in your heart and your spirit, knowing that the demons put ideas into you so as to corrupt your soul by making it think of that which is not right, in order to turn your spirit from the consideration of your sins and of God.
When a man gives God his secret things, that is, his mind and thoughts, not occupying himself elsewhere, nor wandering away, but putting constraint upon himself, then the Lord deems him worthy of mysteries, in greater sanctity and purity, and gives him heavenly food and spiritual drink
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).
We make mention [in the Divine Liturgy] also of the Seraphim, whom Isaiah in the Holy Spirit saw standing around the throne of God, and with two of their wings veiling their face, and with two their feet, while with two they did fly, crying 'Holy, Holy, Holy, is the Lord of Hosts' (Isaiah 6:2-3). For the reason of our reciting this confession of God, delivered down to us from the Seraphim, is this, that so we may be partakers with the hosts of the world above in their hymn of praise.
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.
Unless humility and love, simplicity and goodness regulate our prayer, this prayer - or, rather, this pretence of prayer - cannot profit us at all. And this applies not only to prayer, but to every labor and hardship undertaken for the sake of virtue.
He shall be known by his crimes of inhumanity and lawlessness, so as to outdo all unrighteous and ungodly men who have gone before him; displaying against all men, but especially against us Christians, a spirit murderous and most cruel, merciless and crafty.
But a sober and prudent man who desires to be saved, when he sees from what it is that he suffers harm, carefully preserves himself from evil remembrances, is not drawn into passionate thoughts, avoids meetings and conversations with those for whom he feels attraction and avoids every occasion for sin, fearing lest he himself ignite a fire within himself. This is the warfare which proceeds from one’s own lust, which a man brings on himself
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.
For as merchants on a voyage, though they find a wind to suit them and the sea calm, but have not yet reached the haven, are always subject to fear, lest suddenly a contrary wind should stir and the sea rise into billows, and the ship be in peril, so Christians, even if they have in themselves a favorable wind of the Holy Spirit blowing, are nevertheless yet subject to fear, lest the wind of the adverse power should rise and blow on them, and stir disturbance and billows for their souls. There is need therefore of great diligence, that we may arrive at the haven of rest, at the perfect world, at the eternal life and pleasure, at the city of the saints, at the heavenly Jerusalem, at the church of the firstborn (Heb. xii. 23.). Unless a man gets through these measures, he is under much fear, lest in the meantime the evil power should effect some fall.
When anyone is disturbed or saddened under the pretext of a good and soul-profiting matter, and is angered against his neighbor, it is evident that this is not according to God: for everything that is of God is peaceful and useful and leads a man to humility and to judging himself.
Christians should judge no one, neither an open harlot, nor sinners, nor dissolute people, but should look upon all with simplicity of soul and a pure eye. Purity of heart, indeed, consists in seeing sinful and weak men and having compassion for them and being merciful.
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.
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.
They asked Abba Macarius, 'How should we pray?' And the old man replied, 'There is no need to speak much in prayer; often stretch out your hands and say, 'Lord, as you will and as you know, have mercy on me.' But if there is war in your soul, add, 'Help me!' and because he knows what we need, he shows mercy on us.'
We then commemorate also those who have fallen asleep before us, first, patriarchs, prophets, apostles, martyrs, that God, by their prayers and intercessions, may receive our petitions.