Allah SWT says: وَإِنْ كُنْتُمْ فِى رَيْبٍ مِّمَّا نَزَّلْنَا عَلٰى عَبْدِنَا فَأْتُوا بِسُورَةٍ مِّنْ مِّثْلِهِۦ وَادْعُوا شُهَدَآءَكُمْ مِّنْ دُونِ اللَّهِ إِنْ كُنْتُمْ صٰدِقِينَ "And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful." (QS. Al-Baqara 2: Verse 23) * Via Qur'an English http://quran-en.com