 Muslims state that some who teach memorization/recitation of the Quran constitute the end of an "un-broken chain" whose original teacher was Muhammad himself.It has been argued that "the Qur’an’s rhythmic style and eloquent expression make it easy to memorize," and was made so to facilitate the "preservation and remembrance" of the work.Islamic doctrine holds that from the time it was revealed to the present day, the Quran has not been altered, 
its continuity from divine revelation to its current written form insured by the large numbers of Muhammad's supporters who had reverently memorized the work, a careful compiling process and divine intervention.