To understand the extreme lengths to which the Sufis were prepared to go in reading esoteric meanings into the quite simple language of their Scriptures, it is necessary to remember that the Koran was committed to memory by all deeply religious men and women, and recited constantly, aloud or in the heart; so that the mystic was in a state of uninterrupted meditation upon the Holy Book. Many passages which would otherwise pass without special notice were therefore bound to arrest their attention, already sufficiently alert, and to quicken their imagination, already fired by the discipline of their austerities and the rigor of their internal life.