{ Indeed religion in the sight of Allah is Islam, and those who have been given the book have not differed, except after knowledge came to them, out of agression among themselves. And whoever disbelieves in the signs of Allah, indeed Allah is quick to reckon } Al ‘Imran 19

The word of the Most High: { Indeed religion in the sight of Allah is Islam } ; a declaration from the Most High that there is no religion in His sight that He accepts other than Islam; this is adherence to the messengers in what Allah sent them forth with throughout the ages, until they were sealed by Muhammad (SAW), who closed off every path to Him except from the direction of Muhammad (SAW). Whoever faces Allah after the mission of Muhammad (SAW) with a religion founded on anything other than His law [shari’ah] – it is not accepted, as the Most High says: { Whoever aspires to a religion other than Islam, it will not be accepted of him } [Al ‘Imran 85]. … Then the Most High says: { And whoever disbelieves in the signs of Allah } ; that is, whoever controverts what Allah has sent down in His book, { Indeed Allah is quick to reckon } : that is, indeed Allah will discipline him for this, hold him accountable for his repudiation, and punish him for opposing His book.