Self-flagellation is the disciplinary and devotional practice of flogging oneself with whips or other instruments that inflict pain. In Christianity, self-flagellation is practiced in the context of the doctrine of the mortification of the flesh and is seen as a spiritual discipline. It is often used as a form of penance and is intended to allow the flagellant to share in the sufferings of Jesus, bringing his or her focus to God. The main religions that practice self-flagellation include Christianity and Judaism. The ritual has also been practiced among members of several Egyptian and Greco-Roman cults. Mortification of the flesh Historically, Christians have engaged in various forms of mortification of the flesh, ranging from self-denial, wearing hairshirts and chains, fasting, and self-flagellation (often using a type of whip called a discipline). Some Christians use excerpts from the Bible to justify this ritual. For example, some interpreters claim that Paul the Apostle's statement, "I chastise my body" (1 Corinthians 9:27), refers to self-inflicted bodily scourging. Prominent Christians who have practiced self-flagellation include Martin Luther, the Protestant Reformer, and Congregationalist writer Sarah Osborn, who practiced self-flagellation in order "to remind her of her continued sin, depravity, and vileness in the eyes of God". It became "quite common" for members of the Tractarian movement within the Anglican Communion to practice self-flagellation using a discipline. In the 11th century, Peter Damian, a Benedictine monk in the Roman Catholic tradition, taught that spirituality should manifest itself in physical discipline; he admonished those who sought to follow Christ to practice self-flagellation for the duration of the time it takes one to recite forty Psalms, increasing the number of flagellations on holy days of the Christian calendar. For Damian, only those who shared in the sufferings of Christ could be saved.