From its beginnings the Qur'ān was first and foremost an oral text. When the prophet Muhammad received a revelation, he spoke or recited the revealed text. It is not clear how long these original, spoken units of revelation were, or whether their length was variant or invariant. The relation between these spoken units and Qur'ānic sūras is also unknown. According to the Islamic tradition, however, the revelation of the different sūras followed a chronology of roughly shorter to longer. The earlier ones were rather short and they tended to become longer as Muhammad's mission and prophetic preaching continued.

CODIFICATION AND RECITATION

In addition to being memorised and transmitted orally, these revealed texts were written down during the life of Muhammad, a process that probably began at an early stage. At least, that is what reports about the collection of the Qur'ān after the Prophet's death relate. The commission under Zayd b. Thābit (d. 32/652-3), which provided the edition of the Qur'ānic text that subsequently became known as the 'Uthmānic codex, based its work on oral material, and on all kinds of written material, such as texts on scraps of wood, palm leaves, bark and bones. Zayd himself is said to have been ordered by Muhammad to record verses of the Qur'ān on the shoulder blade of a camel immediately after a revelation. An older Companion of Muhammad, 'Abdallāh b. Mas'ūd, is reported to have said that he had already written down seventy sūras from the mouth of the Prophet when Zayd was still playing with other little boys.