Surah 20. Ta-Ha, Ayah 99

The adverb kadhalika ("thus") which introduces this verse is meant to stress the purpose of all Qur'anic references to past events - be they historical or legendary - as well as the manner in which the relevant stories are treated. Since the purpose underlying every Qur’anic narrative is, invariably, the illustration of certain fundamental truths, the narrative as such is often condensed and elliptic, omitting all that has no direct bearing on the point or points which the Qur’an means to bring out. The term "reminder" alludes to the unceasing guidance which God offers to man through His revelations.

 The Quran.

Thus superseding previous revelations; for this (the Qur-an) is direct from Allah, and is not a second-hand exposition on other men's authority.