John the Faster (John IV, called Nesteutes, 'the Faster') was Patriarch of Constantinople from 582 until his death on September 2, 595. Born at Constantinople to a family of artisans, he worked as an engraver or goldsmith before entering the service of the Church, and he is remembered above all for the extreme rigor of his fasting and the depth of his personal humility.
Under Patriarch John III Scholasticus he served as a deacon at the Great Church of Hagia Sophia and then as sakellarios, the patriarchal official responsible for the oversight of monasteries. After the death of Patriarch Eutychius in 582 he was raised to the patriarchal throne; the tradition relates that he accepted the office only with great reluctance, and the sources note that he had a wide reputation for asceticism and for charity to the poor while possessing little formal learning.
His name remained attached to a penitential discipline used in the Eastern Church: a rule, or nomokanon, guiding priests in the hearing of confession. The penitential ascribed to him addressed both sins of act and sins of intention and, in the synaxarion tradition, tempered the older canonical penances, weighing the severity of fasting, prostrations, and almsgiving in the direction of mercy. This canon long guided confessors in the Byzantine world.
The Orthodox Church commemorates him on September 2, with a further commemoration on August 30. By tradition he is honored as a model of fasting and of monastic humility, and the Western sources record that at his death he left no possessions but a cloak, a blanket, and a praying-stool.