Concise Quran Commentary
Allah challenges those who have any doubt about the Qur’ān revealed to His servant, Muhammad (peace be upon him), to produce a chapter just like it, and to call their helpers, if they are truthful about what they say.
وَإِن كُنتُمْ فِى رَيْبٍ مِّمَّا نَزَّلْنَا عَلَىٰ عَبْدِنَا فَأْتُوا۟ بِسُورَةٍ مِّن مِّثْلِهِۦ وَٱدْعُوا۟ شُهَدَآءَكُم مِّن دُونِ ٱللَّهِ إِن كُنتُمْ صَـٰدِقِينَ
If you are in doubt concerning that which We have sent down upon Our slave[15], then produce a chapter like it and call upon your helpers other than Allah, if you are truthful.