Assalamu 'alaikum

And if ye are in doubt as to what We have revealed from time to time to Our servant, then produce a Sura like thereunto; and call your witnesses or helpers (If there are any) besides Allah, if your (doubts) are true.

But if ye cannot- and of a surety ye cannot- then fear the Fire whose fuel is men and stones,- which is prepared for those who reject Faith.

Surah Baqarah ayah 23 and 24.