Surah Al-Baqarah (The Cow), Verse 23

وَاِنْ كُنْتُمْ فِیْ رَیْبٍ مِّمَّا نَزَّلْنَا عَلٰی عَبْدِنَا فَاْتُوْا بِسُوْرَةٍ مِّنْ مِّثْلِهٖ وَادْعُوْا شُهَدَآءَكُمْ مِّنْ دُوْنِ اللّٰهِ اِنْ كُنْتُمْ صٰدِقِیْنَ ۟

Wa in kuntum fee raibim mimmaa nazzalnaa 'alaa 'abdinaa fatoo bi Sooratim mim mislihee wad'oo shuhadaaa'akum min doonil laahi in kuntum saadiqeen

“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.”

Quran 2:23 (Yusuf Ali Translation)