Two quotes from The Prayer of Love and Silence by a Carthusian.

“Obedience and patience, we must remember, are not ends in themselves. ‘Art for art’s sake’ is nonsense, since nothing created can be its own end. It is the same with virtue. ‘Virtue for virtue’s sake’ as an ideal is meaningless and discouraging, because it can never be realized. Anyone leaving the world for the paltry pleasure of thinking himself perfect, or who accepts the world’s challenges from a sense of spiritual pride or to increase his self-esteem is simply ending up where he began—with himself!”

“The divine life can only take possession of us when we have done all we can, on our part, to become detached from created things. Death to self and life in God are inseparably linked: the one without the other remains sterile.”