Asceticism is a term used to describe the practice of self-discipline. Often through self-denial or the mastering of desires (fasting involves control over the passion for food, a vigil requires control over the urge to sleep). For a religious end such as repentance, worship, the cultivation of virtue, or union or communion with God. Asceticism is widespread among religious traditions, theistic and non-theistic. Buddhist ascetic, practices are closely linked with the purging of desire and seeing through the illusory nature of ourselves as substantial beings.