It is one of the more dramatic and controversial aspects of the Catholic movement Opus Dei: corporal mortification.
Mortification, which literally means "to make death," is a method of killing everyday temptations that distract from God. When a Christian gives up something for Lent, that is a form of mortification.
Generally, only numerary members (celibate lay people and priests) of Opus Dei -- male and female -- practice the kind of corporal mortification involving two celebrated methods of producing physical discomfort: the cilice and the discipline. Numeraries make up about a quarter of Opus Dei's membership.
The cilice is a spiked chain worn around the leg for two hours a day, and the discipline is a whip often used while reciting the Lord's Prayer. Opus Dei members stress that these devices are used to produce pain but do not threaten their health.
The medieval nature of corporal mortification suggests to many outside Opus Dei that the organization is a backward and masochistic cult, and the movement's leaders attempt to dispel that notion. They write on their Web site that the use of the cilice and discipline "is motivated by love of God and desire to unite oneself with Jesus Christ, not guilt, self-hatred or self-punishment."
The Rev. Michael Geisler, spiritual director of Opus Dei in St. Louis, has written two articles this summer attempting to explain the theological purpose behind corporal mortification.
Both articles, he said, were in response to the depiction of Opus Dei and the practice of corporal mortification itself in Dan Brown's 2003 novel The Da Vinci Code. In the book, one of the protagonists is an Opus Dei member who commits murder and then punishes himself using violent versions of corporal mortification.
Geisler said that while it is the cilice and discipline that get the most attention, mortification can take on less dramatic forms. A cold shower, for instance, is a typical way for members of Opus Dei to "discipline the lustful guy inside," said Geisler.
Mortification can be as simple as waiting a few minutes before drinking water when thirsty, or eating a hated vegetable.
"Self-denial helps a person overcome both psychological and physical weakness, gives him energy, helps him grow in virtue and ultimately leads to salvation," wrote Geisler in a defense of corporal mortification in the July/August issue of Crisis magazine.
"It conquers the insidious demons of softness, pessimism and lukewarm faith that dominate the lives of so many today."