(Say:) ‘Should I look for someone other than Allah as authority (and judge) while He (Allah) is the One Who has revealed to you the elaborate Book (comprising a clear course of action). And those whom We gave the Book (before) know (with conviction) that this (Qur’an) has been revealed from your Lord (based on) Truth. So do not be of the sceptics (with regard to these People of the Book whether they know or not that the Qur’an is a revealed Book).