Quran 17:88 from Surah Al-Israa on Divine Marvels.
قُل لَّئِنِ ٱجۡتَمَعَتِ ٱلۡإِنسُ وَٱلۡجِنُّ عَلَىٰٓ أَن يَأۡتُواْ بِمِثۡلِ هَٰذَا ٱلۡقُرۡءَانِ لَا يَأۡتُونَ بِمِثۡلِهِۦ وَلَوۡ كَانَ بَعۡضُهُمۡ لِبَعۡضٖ ظَهِيرٗا
English translation: Say If gathered the mankind and the jinn to [that] bring the like (of) this Quran not they (could) bring the like of it even if were some of them to some others assistants
Transliteration: qul la-ini ij'tama'ati al-insu wal-jinu ala an yatu bimith'li hadha al-qur'ani la yatuna bimith'lihi walaw kana ba'duhum liba'din zahiran