Qur'ān 10:38 · Yunus (يونس)

أَمْ يَقُولُونَ ٱفْتَرَىٰهُ ۖ قُلْ فَأْتُوا۟ بِسُورَةٍۢ مِّثْلِهِۦ وَٱدْعُوا۟ مَنِ ٱسْتَطَعْتُم مِّن دُونِ ٱللَّهِ إِن كُنتُمْ صَـٰدِقِينَ

Or do they say [about the Prophet], "He invented it?" Say, "Then bring forth a surah like it and call upon [for assistance] whomever you can besides Allah, if you should be truthful."