A soul arms itself by prayer for all kinds of combat. In whatever state the soul may be, it ought to pray. A soul which is pure and beautiful must pray, or else it will lose its beauty; a soul which is striving after purity must pray, or else it will never attain it; a soul which is newly converted must pray, or else it will fall again; a sinful soul, plunged in sins, must pray so that it might rise again. There is no soul which is not bound to pray, for every single grace comes to the soul through prayer.

From the Diary of Saint Maria Faustina Kowalska paragraph 146