اَمۡ يَقُوۡلُوۡنَ افۡتَرٰىهُؕ قُلۡ فَاۡتُوۡا بِسُوۡرَةٍ مِّثۡلِهٖ وَادۡعُوۡا مَنِ اسۡتَطَعۡتُمۡ مِّنۡ دُوۡنِ اللّٰهِ اِنۡ كُنۡتُمۡ صٰدِقِيۡنَ

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