Hesychasm, from the Greek hesychia, stillness or quiet, is the contemplative tradition of Eastern Orthodox Christianity that seeks inner silence and unceasing prayer of the heart. Its practical core is the Jesus Prayer, a short invocation, most fully "Lord Jesus Christ, Son of God, have mercy on me, a sinner", repeated continuously until it descends from the lips into the mind and from the mind into the heart, and finally continues of itself without deliberate effort, fulfilling the apostolic injunction to pray without ceasing. The repetition is often synchronised with the breath and counted on a knotted woollen cord, and it is aimed at gathering the scattered mind, uniting it with the heart, and holding the practitioner in the continual remembrance of God.
The tradition grew from the desert monasticism of Egypt and Sinai, was developed on Mount Athos, and is gathered in the Philokalia, the great anthology of ascetic and contemplative texts compiled in the eighteenth century that spread the practice through the Orthodox world and, through works such as the Russian "Way of a Pilgrim," far beyond the monasteries.