The Spirits' Book
Book Three - Moral Laws
Chapter V - IV. Law of Preservation
Voluntary Deprivations – Mortifications
721. Throughout the course of time and among all populations, there have been those who have lived a life of ascetic mortification. Is an ascetic life ever praiseworthy?
“Ask yourselves to whom such a life is useful, and you will have the answer to your question. If such a life only serves the person who leads it and it prevents that person from doing good, it is a form of selfishness, regardless of the pretext it hides behind. True mortification, according to Christian charity, is to impose self-deprivation and work upon yourself for the benefit of others.”