Surah Al-Isra' (The Night Journey), Verse 88

قُلْ لَّىِٕنِ اجْتَمَعَتِ الْاِنْسُ وَالْجِنُّ عَلٰۤی اَنْ یَّاْتُوْا بِمِثْلِ هٰذَا الْقُرْاٰنِ لَا یَاْتُوْنَ بِمِثْلِهٖ وَلَوْ كَانَ بَعْضُهُمْ لِبَعْضٍ ظَهِیْرًا ۟

Qul la'inij tama'atil insu waljinnu 'alaaa any ya'too bimisli haazal quraani laa ya'toona bimislihee wa law kaana ba'duhum liba 'din zaheeraa

“Say: "If the whole of mankind and Jinns were to gather together to produce the like of this Qur'an, they could not produce the like thereof, even if they backed up each other with help and support.”

Quran 17:88 (Yusuf Ali Translation)