“No mental state is less creative than mild sadness, the very negation of inspiration. Everything depends on the level of sadness, on the frequency of its vibrations. At a certain level it is poetical, at another musical, and finally religious. Thus there are different kinds of sadness: of poets, of musicians, of saints. The sadness of poets or musicians leaves their heart, goes around the world, and returns like an echo. The sadness of saints also leaves the heart but it stops in God, thus fulfilling every saint's secret wish, to become his prisoner.”
Book:Tears and Saints