1. Of the demons opposing us in the practice of the ascetic life, there are three groups who fight in the front line: those entrusted with the appetites of gluttony, those who suggest avaricious thoughts, and those who incite us to seek the esteem of men. All the other demons follow behind and in their turn attack those already wounded by the first three groups. For one does not fall into the power of the demon of unchastity, unless one has first fallen because of gluttony; nor is one's anger aroused unless one is fighting for food or material possessions or the esteem of men. And one does not escape the demon of dejection, unless one no longer experiences suffering when deprived of these things. Nor will one escape pride, the first offspring of the devil, unless one has banished avarice, the root of all evil, since poverty makes a man humble, according to Solomon (cf. Prov. 10:4. LXX). In short, no one can fall into the power of any demon, unless he has been wounded by those of the front line. That is why the devil suggested these three thoughts to the Savior: first he exhorted Him to turn stones into bread; then he promised Him the whole world, if Christ would fall down and worship him; and thirdly he said that, if our Lord would listen to him, He would be glorified and suffer nothing in falling from the pinnacle of the temple. But our Lord, having shown Himself superior to these temptations, commanded the devil to 'get behind Him'. In this way He teaches us that it is not possible to drive away the devil, unless we scornfully reject these three thoughts (cf. Matt. 4:1-10).
2. All thoughts inspired by the demons produce within us conceptions of sensory objects; and in this way the intellect, with such conceptions imprinted on it, bears the forms of these objects within itself. So, by recognizing the object presented to it, the intellect knows which demon is approaching. For example, if the face of a person who has done me harm or insulted me appears in my mind, I recognize the demon of rancor approaching. If there is a suggestion of material things or of esteem, again it will be clear which demon is troubling me. In the same way with other thoughts, we can infer from the object appearing in the mind which demon is close at hand, suggesting that object to us. I do not say that all thoughts of such things come from the demons; for when the intellect is activated by man it is its nature to bring forth the images of past events. But all thoughts producing anger or desire in a way that is contrary to nature are caused by demons. For through demonic agitation the intellect mentally commits adultery and becomes incensed. Thus it cannot receive the vision of God, who sets us in order; for the divine splendor only appears to the intellect during prayer, when the intellect is free from conceptions of sensory objects.
3. Man cannot drive away impassioned thoughts unless he watches over his desire and incensive power. He destroys desire through fasting, vigils and sleeping on the ground, and he tames his incensive power through long-suffering, forbearance, forgiveness and acts of compassion. For with these two passions are connected almost all the demonic thoughts which lead the intellect to disaster and perdition. It is impossible to overcome these passions unless we can rise above attachment to food and possessions, to self-esteem and even to our very body, because it is through the body that the demons often attempt to attack us. It is essential, then, to imitate people who are in danger at sea and throw things overboard because of the violence of the winds and the threatening waves. But here we must be very careful in case we cast things overboard just to be seen doing so by men. For then we shall get the reward we want; but we shall suffer another shipwreck, worse than the first, blown off our course by the contrary wind of the demon of self-esteem. That is why our Lord, instructing the intellect, our helmsman, says in the Gospels: 'Take heed that you do not give alms in front of others, to be seen by them; for unless you take heed, you will have no reward from your Father in heaven.' Again, He says: 'When you pray, you must not be as the hypocrites are: for they love to pray standing in synagogues and at street-corners, so as to be seen by men. Truly I say to you, they get the reward they want. . . Moreover when you fast, do not put on a gloomy face, like the hypocrites; for they disfigure their faces, so that they may be seen by men to be fasting. Truly I say to you, they get the reward they want' (cf. Matt. 6: 1-18). Observe how the Physician of souls here corrects our incensive power through acts of compassion, purifies the intellect through prayer, and through fasting withers desire. By means of these virtues the new Adam is formed, made again according to the image of his Creator - an Adam in whom, thanks to dispassion, there is 'neither male nor female' and, thanks to singleness of faith, there is 'neither Greek nor Jew, circumcision nor uncircumcision, barbarian, Scythian, bond nor free; but Christ is all, and in all' (Gal. 3:28; Col. 3: 10:11).
Evagrios the Solitary, Text on Discrimination in Respect of Passions & Thoughts
Just as the eye cannot see a grain of wheat unless the eyelids are open, so the practical intellect cannot see its own nature unless stripped of the attachment to sensible things that obscures its vision.
When bitten by some wild animal, a deer runs swiftly to earthly springs of water; a soul wounded by the most tender arrow of prayer hastens towards the light of incorporeal realities.
The inner principles of corporeal realities are concealed like bones within objects apprehended by the senses: no one who has not transcended attachment to sensible things can see them.
When the stage of ascetic practice has been fulfilled, spiritual visions flood the intellect like the sun's rays coming over the horizon; even though they are native to it, and embrace it because of its purity, they appear to come from outside.
Ilias the Presbyter
If you give in and are defeated when a swarm of evil thoughts rises up against you in your mind, you should know that for a time you have been cut off from the grace of God, and by His just sentence abandoned to your fate. Make every effort, then, never through your own negligence to be deprived of grace, even for a single moment. If you manage to avoid falling, if you succeed in leaping over the barrier formed by impassioned thoughts, and if you overcome the unclean provocations that the enemy in his ingenuity continually suggests to you, do not ignore the gift conferred on you from above. As the Apostle says, 'It was not I but the grace of God which was with me' (1Cor. 15:10) that won this victory, raising me above the impure thoughts that assailed me. It was His grace that 'delivered me from the wicked man' (cf. Ps. 18:48. LXX), that is, from the devil and from the 'old man' within me (cf. Rom. 6:6). Lifted by the wings of the Spirit and freed from the weight of my body, I was able to soar above the predatory demons, who catch man's intellect with the bird-lime of sensual indulgence, tempting it in a forcible and violent manner. It was God who brought me out from the land of Egypt, that is, from the soul-destructiveness of the world; it was God who fought on my behalf and with His unseen hand put Amalek to flight (cf. Exod. 17:8-16), thus giving me cause to hope that He will also drive out the other tribes of impure passions before me. He is our God, and will give us both 'wisdom and power' (Dan. 2:23); for some have received wisdom but not the power of the Spirit to defeat their enemies. He will 'lift up your head above your enemies' (cf. Ps. 27:6);
St. John of Karpathos
Seeing, therefore, that we are the portion of the Holy One, let us do all those things which pertain to holiness, avoiding all evil-speaking, all abominable and impure embraces, together with all drunkenness, seeking after change, all abominable lusts, detestable adultery, and execrable pride. "For God," saith [the Scripture], "resisteth the proud, but giveth grace to the humble." Let us cleave, then, to those to whom grace has been given by God. Let us clothe ourselves with concord and humility, ever exercising self-control, standing far off from all whispering and evil-speaking, being justified by our works, and not our words. For [the Scripture] saith, "He that speaketh much, shall also hear much in answer. And does he that is ready in speech deem himself righteous? Blessed is he that is born of woman, who liveth but a short time: be not given to much speaking." Let our praise be in God, and not of ourselves; for God hateth those that commend themselves. Let testimony to our good deeds be borne by others, as it was in the case of our righteous forefathers.
St. Clement, to the Corinthians
For our Lord was made man; He was condemned that He might impart compassion; He was bound that He might set free; He was apprehended that He might liberate; He suffered that He might heal our sufferings; He died to restore life to us; He was buried to raise us up. For when our Lord suffered, His humanity suffered, that which He had like unto man; and He dissolves the sufferings of him who is His like, and by dying He hath destroyed death. It was for this cause that He came down upon earth, that by pursuing death He might kill the rebel that slew men. For one underwent the judgment, and myriads were set free; one was buried, and myriads rose again. He is the Mediator between God and man; He is the resurrection and the salvation of all; He is the Guide of the erring, the Shepherd of men who have been set free, the life of the dead, the charioteer of the cherubim, the standard-bearer of the angels, and the King of kings, to whom be glory for ever and ever. Amen.
... And besides the pious opinion concerning the Father and the Son, we confess to one Holy Spirit, as the divine Scriptures teach us; who hath inaugurated both the holy men of the Old Testament, and the divine teachers of that which is called the New. And besides, also, one only Catholic and Apostolic Church, which can never be destroyed, though all the world should seek to make war with it; but it is victorious over every most impious revolt of the heretics who rise up against it. For her Goodman hath confirmed our minds by saying, "Be of good cheer, I have overcome the world." After this we know of the resurrection of the dead, the first-fruits of which was our Lord Jesus Christ, who in very deed, and not in appearance merely, carried a body, of Mary Mother of God, who in the end of the world came to the human race to put away sin, was crucified and died, and yet did He not thus perceive any detriment to His divinity, being raised from the dead, taken up into heaven, seated at the right hand of majesty.
These things in part have I written in this epistle, thinking it burdensome to write out each accurately, even as I said before, because they escape not your religious diligence. Thus do we teach, thus do we preach. These are the apostolic doctrines of the Church, for which also we die, esteeming those but little who would compel us to forswear them, even if they would force us by tortures, and not casting away our hope in them.
St. Alexander of Alexandria, d. 326 A.D.