Ulum al Qur'an
Seven Modes in the Qur'an
While some scholars [e.g. Tabari, Jami' al-bayan 'an ta'wil ayat al-Qur’an, Cairo, 1968. See introduction to this tafsir. Zarkashi, Vol. 1, p.213 says most scholars are of the first view, and that the last double-reading of the Qur'an by Muhammad in the presence of the Angel Gabriel served, among others, the purpose of eliminating the other six modes.] hold that the written Qur'an now includes only one of the 'seven modes', and the others are transmitted orally to us, there is some evidence also for the view that the text of the Qur'an, as we have it in front of us, may include all these 'seven modes' because:
No one would change the Qur'an.
The present text was written upon the basis of the sahaba testimonies, both orally and written, going back directly to the Prophet.