Heroic asceticism and self-injurious behavior

Why did medieval ascetics practice asceticism? The medieval sources tell us that such behavior was motivated by identification with Christ’s passion, service to God, renunciation of the flesh, subordination of the physical to the spiritual, penance for the sins of other individuals or for all of humankind, penance for one’s own sins, and combat with the devil. Underlying these reasons were, to varying degrees, the desire to move closer to God and the assumption that carnal thoughts and preoccupations interfered with attainment of this goal.1