There was certainly in their stories a lesson for those of understanding. Never was it [i.e., the Qur’ān] a narration invented, but a confirmation of what was before it and a detailed explanation of all things and guidance and mercy for a people who believe.
In the stories of the messengers and their peoples, as in the story of Joseph and his brothers, are lessons to be learnt by those of sound mind. The Qur’ān, which contains such narrations, is not words which are made up and fabricated about Allah, but a confirmation of the divine scriptures revealed from Allah and a detailed explanation of everything that needs explaining through sacred laws; and guidance to all that is good, and a mercy for those who have faith in it, because it is they who benefit from what is in it.