And if you are in doubt about what We have sent down [i.e., the Qur'an upon Our Servant [i.e., Prophet Muúammad ()], then produce a s´rah the like thereof and call upon your witnesses [i.e., supporters] other than Allah, if you should be truthful.

But if you do not – and you will never be able to – then fear the Fire, whose fuel is people and stones, prepared for the disbelievers.

Quran ( 2 : 24 _ 23 )