"And if you are in doubts concerning that which We have sent down (i.e. the Qur'an) to Our slave, then produce a Surah (chapter) of the like thereof and call your wit nesses (supporters and helpers) beside Allah, if you are truthful"
Holy Quran 2:23
"And
if you are in doubts concerning that which We have sent down (i.e.
the Qur'an) to Our slave, then produce a Surah (chapter) of the
like thereof and call your wit nesses (supporters and helpers)
beside Allah, if you are truthful" 
