Sura al-Isrāʾ 17:88

قُل لَّئِنِ ٱجْتَمَعَتِ ٱلْإِنسُ وَٱلْجِنُّ عَلَىٰٓ أَن يَأْتُوا۟ بِمِثْلِ هَٰذَا ٱلْقُرْءَانِ لَا يَأْتُونَ بِمِثْلِهِۦ وَلَوْ كَانَ بَعْضُهُمْ لِبَعْضٍ ظَهِيرًا

qul llaini ijtamaʿati l-insu wa-l-jinnu ʿala an yaʾtū bi-mithli hādhā l-qurʾāni lā yaʾtūna bimithlihi wa-law kāna baʿḍuhum li-baʿḍin ẓahīran

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.