Surah Hud (Hud), Verse 13

اَمْ یَقُوْلُوْنَ افْتَرٰىهُ قُلْ فَاْتُوْا بِعَشْرِ سُوَرٍ مِّثْلِهٖ مُفْتَرَیٰتٍ وَّادْعُوْا مَنِ اسْتَطَعْتُمْ مِّنْ دُوْنِ اللّٰهِ اِنْ كُنْتُمْ صٰدِقِیْنَ ۟

Am yaqooloonaf taraahu qul faatoo bi'ashri Suwarim mislihee muftarayaatinw wad'oo manis tata'tum min doonil laahi in kuntum saadiqeen

“Or they may say, "He forged it," Say, "Bring ye then ten suras forged, like unto it, and call (to your aid) whomsoever ye can, other than Allah!- If ye speak the truth!”

Quran 11:13 (Yusuf Ali Translation)