Saint Nikitas Stithatos. "On the Inner Nature of Things and on the Purification of the Intellect: One Hundred Texts". From Philokalia, Vol. 4.
60. Those who have attained spiritual maturity can also analyze, the impulsions and proclivities of the soul, and can guide and guard their inner state, on the basis of dreams. For bodily impulsions and the images in our intellect depend upon our inner disposition and preoccupations. If your soul hankers after pleasure and material things, you will dream about acquiring possessions and having money, about the female figure and sexual intercourse - all of which leads to the soiling and defilement of soul and body. If you are haunted by images of greed and avarice, you will see money everywhere, will get hold of it, and will make more money by lending it out at interest and storing the proceeds in the bank, and you will be condemned for your callousness. If you are hottempered and vicious, images of poisonous snakes and wild beasts will plague you and overwhelm you with terror. If you are fall of self-esteem, you will dream of popular acclaim and mass-meetings, government posts and high office; and even when awake you will imagine that these things, which as yet you lack, are already yours, or soon will be. If you are proud and pretentious, you will see yourself being carried along in a splendid coach and even sometimes airborne, while everyone trembles at your great power. Similarly, if you are devoted to God, diligent in the practice of the virtues, scrupulous in the struggle for holiness and with a soul purged of material preoccupations, you will see in sleep the outcome of events and awe-inspiring visions will be disclosed to you. When you wake from sleep you will always find yourself praying with compunction and in a peaceful state of soul and body, and there will be tears on your cheeks, and on your lips words addressed to God.
61. The images that visit us during sleep are either dreams, or visions, or revelations. To the category of dreams belongs everything in the image-forming faculty of the intellect that is mutable - all that makes it confused and subject to constantly altering states. We have nothing to gain from such images and if we are sensible we should ignore them - indeed, they disappear of their own accord as soon as we awake. Visions on the other hand are constant; the one does not change into another, but they remain imprinted upon the intellect unforgettably for many years. Those that disclose the upshot of things to come, and assist the soul by inspiring it with compunction and the sight of fearful wonders, make the beholder reflective and strike him with awe on account of their constancy and their fearsome nature. Hence they are treated with great seriousness by those skilled in spiritual matters. Revelations occur when the purified and illumined soul is able to contemplate in a way that transcends normal sense-perception. They have the force of things and thoughts miraculous and divine, initiating us into the hidden mysteries of God, showing us the outcome of our most important problems and the universal transformation of things worldly and human.
62. The first category - that of dreams - pertains to materialistic sensually-minded people who worship their belly (cf. Phil. 3:19) and are brash in their over-indulgence. Their dissolute, passion-polluted mode of life darkens their intellect, and they are mocked and spellbound by the demons. The second category - that of visions -pertains to those well advanced on the spiritual path, who have cleansed the soul's organs of perception. Beneficially assisted by things visible they ascend to the ever-increasing apprehension of things divine. The third category - that of revelations - pertains to those who are perfect, who are energized by the Holy Spirit, and whose soul through mystical prayer is united to God.
63. Things seen in sleep are true and imprinted on the spiritual intellect in the case, not of everyone, but only of those whose intellect is purified, who have cleansed the soul's organs of perception and who are advancing toward the contemplation of the inner essences of created things. Such people do not worry about day-to-day matters, nor are they troubled about this present life. Through long fasts they have acquired an all-embracing self-control and through exertion and hardship they' have attained the sanctuary of God, the spiritual knowledge of created being and the wisdom of the higher world. Their life is the life of angels and is hidden in God (cf. Col. 5:3), their progress is based upon holy stillness and on the prophets of God's Church. It is of them that God has spoken through Moses, when He said, 'If there be a prophet among you, I will appear to him in his sleep and will speak to him in a vision' (cf. Num. 12:6); and through Joel, when He said, 'And it will come to pass after these things that I will pour out My spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams and your young men shall see visions' (Joel 2:28).