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.
Memorization has gotten a bad rap recently. Lots of students, and even some educators, say that being able to reason is more important than knowing facts; and besides, why bother committing things to memory when you've got Google? My response to this - after I've finished inwardly groaning - is that of course reasoning is important, but that doesn't mean you shouldn't know facts as well. It's not like you have to choose between one or the other. Besides, facts give you a foundation on which to reason about things.