A term applied to three distinct but related stages of development of Eastern Christian spirituality. The term comes from the Greek word meaning “tranquility.”
First, hesychasm refers to the spirituality which was characteristic of the early Church Fathers in the 4th and 5th centuries. These monks were hermits dwelling in the deserts seeking inner peace and spiritual insight while practicing contemplation and self-discipline as they studied the New Testament and the Psalter.
Secondly, hesychasm refers to the type of contemplation which developed with the Byzantine spirituality from the 10th to the 14th centuries. Such spirituality employed the method of praying the Jesus Prayer “(Lord Jesus Christ, Son of God, have mercy on me a sinner.)” The saying of the pray was synchronized with one’s breathing. This spiritual practice is characteristic of the spirituality described in the five volume collection called Philokalia.
Thirdly, hesychasm refers to the theological exposition of the contemplation of God as proposed by Gregory Palamas in the 14th century and became the official doctrine of the Orthodox Church.
Plamas’ aimed for this proposal was to defend the hesychastic spirituality and the way of prayer of the monks of Mt. Athos and the Byzantine Orient against the attacks of the Barlaam Calabria.
Palamas distinguished between the unchanging essence of God and His uncreative energies. “The Taboric Light (the light that surrounded Christ in the Transfiguration), the goal sought in contemplation by the hesychasts, was a theophany, or manifestation of God, through His uncreated energies.” A.G.H.
Source:(Hesychasm, George A. Maloney, S.J., John, XXIII Center, Fordham University) 61.