To deprive oneself of the gratification of the appetites in all things is like living in darkness and in a void. ... Hence, we call this nakedness a night for the soul. For we are not discussing the mere lack of things; this lack will not divest the soul., if it [still] craves for all these objects. We are dealing with the denudation of the soul's appetites and gratifications; this is what leaves it free and empty of all things, even though it possesses them. Since the things of the world cannot enter the soul, they are not in themselves an encumbrance or harm to it; rather, it is the will and appetite dwelling within it that causes the damage.
(Saint John of the Cross)