Hesychasm

Hesychasm (Greek ἡσυχασμός) is an eremitic tradition of prayer in the Eastern Orthodox Church, and some other Eastern Churches of the Byzantine Rite.
Based on Christ's injunction in the Gospel of Matthew to "go into your closet to pray", Hesychasm in tradition has been the process of retiring inward by ceasing to register the senses, in order to achieve an experiential knowledge of God.
Hesychastic practice bears some resemblance to mystical prayer or meditation in Eastern religions (Buddhism, Hinduism, Jainism and Sufism, compare with yoga), although this similarity is often over-emphasized in popular accounts and generally rejected by actual Orthodox practitioners of Hesychasm. The practice may involve specific body postures and be accompanied by very deliberate breathing patterns. However, these bodily postures and breathing patterns are treated as secondary both by modern Athonite practitioners of Hesychasm and by the more ancient texts in the Philokalia, the emphasis being on the primary role of Grace.
Take up your seat on a high place and watch, if only you know how, and then you will see in what manner, when, whence, how many and what kind of thieves come to enter and steal your clusters of grapes. When the watchman grows weary, he stands up and prays; and then he sits down again and courageously takes up his former task.In solitude and retirement the Hesychast repeats the Jesus Prayer, "Lord Jesus Christ, son of God, have mercy on me, a sinner." The Hesychast prays the Jesus Prayer 'with the heart'—with meaning, with intent, 'for real' . He never treats the Jesus Prayer as a string of syllables whose 'surface' or overt verbal meaning is secondary or unimportant. He considers bare repetition of the Prayer as a mere string of syllables, perhaps with a 'mystical' inner meaning beyond the overt verbal meaning, to be worthless or even dangerous. This emphasis on the actual, real invocation of Jesus Christ marks a divergence from Eastern forms of meditation.
The Great Schema or Megaloschema, worn by seasoned hesychasts:
The Hesychast is to bring his mind into his heart so as to practise both the Jesus Prayer and sobriety with his mind in his heart. The descent of the mind into the heart is taken quite literally by the practitioners of Hesychasm and is not at all considered to be a metaphorical expression. Some of the psychophysical techniques described in the texts are to assist the descent of the mind into the heart at those times that only with difficulty it descends on its own.
Theophan the Recluse's famous sayings:
"God abandons no one. For Him all are children. None are step-children. And the hard occasions and situations - all is sent for our benefit."
"Attention to that which transpires in the heart and proceeds from it - this is the chief activity of the proper Christian life."
"You must watch after yourself."
"Descend with your attention into the heart, stand there before the Lord and admit nothing sinful to enter there. In this is the entire activity of inner warfare."
"Mercilessness to oneself, readiness to perform any favor to others and the surrender of oneself entirely to the Lord with a prayerful abiding in Him - these are the creators of the spiritual life."
"You must kill egoism. If you don't kill it yourself, then the Lord, hammer-blow after hammer-blow, shall send various misfortunes, so as to crush this stone."
"Self-pleasing and self-pity testify that in the heart abides the ego, and not the Lord."The guard of the mind is the practical goal of the Hesychast. It is the condition in which he remains as a matter of course throughout his day, every day until he dies. It is from the guard of the mind that he is raised to contemplation by the Grace of God.
The Hesychast usually experiences the contemplation of God as light, the Uncreated Light of the theology of St Gregory Palamas.
The goal is to acquire, through purification and Grace, the Holy Spirit and salvation. Any ecstatic states or other unusual phenomena which may occur in the course of Hesychast practice are considered secondary and unimportant, even quite dangerous. Moreover, seeking after unusual 'spiritual' experiences can itself cause great harm, ruining the soul and the mind of the seeker. Such a seeking after 'spiritual' experiences can lead to spiritual delusion—the antonym of sobriety—in which a person believes himself or herself to be a saint, has hallucinations in which he or she 'sees' angels, Christ, etc. This state of spiritual delusion is in a superficial, egotistical way pleasurable, but can lead to madness and suicide, and, according to the Hesychast fathers, makes salvation impossible.
The Lord seeks a heart filled to overflowing with love for God and our neighbor; this is the throne on which he loves to sit and on which he appears in the fullness of his heavenly glory. Son, give me thine heart, for in the human heart the Kingdom of God can be contained." ---Saint Seraphim de Sarov