Ulum al Qur'an
MEMORISATION AND ORAL TRANSMISSION
Memorisation by the Prophet
Oral transmission of the revelation was based on hifz or memorisation and the Prophet Muhammad himself was the first to commit a revelation to memory after the Angel Gabriel had brought it to him:
'Move not thy tongue concerning the (Qur'an) to make haste therewith. It is for Us to collect it and promulgate it; but when We have promulgated it, follow thou its recital' (75: 16-19).
'... an apostle from God, rehearsing scriptures, kept pure and holy ...' (98: 2).