Quran 11:13 from Surah Hud on Divine Marvels.
أَمۡ يَقُولُونَ ٱفۡتَرَىٰهُۖ قُلۡ فَأۡتُواْ بِعَشۡرِ سُوَرٖ مِّثۡلِهِۦ مُفۡتَرَيَٰتٖ وَٱدۡعُواْ مَنِ ٱسۡتَطَعۡتُم مِّن دُونِ ٱللَّهِ إِن كُنتُمۡ صَٰدِقِينَ
English translation: Or they say He has fabricated it Say Then bring ten surahs like it fabricated and call whoever you can besides Allah besides Allah besides Allah if you are truthful
Transliteration: am yaquluna if'tarahu qul fatu bi'ashri suwarin mith'lihi muf'tarayatin wa-id'u mani is'tata'tum min duni al-lahi in kuntum sadiqina