Surah Yunus, Verse 38
أَمْ يَقُولُونَ ٱفْتَرَىٰهُ ۖ قُلْ فَأْتُوا۟ بِسُورَةٍۢ مِّثْلِهِۦ وَٱدْعُوا۟ مَنِ ٱسْتَطَعْتُم مِّن دُونِ ٱللَّهِ إِن كُنتُمْ صَٰدِقِينَ
Translation — Sahih International
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."
Source
Kur'an-ı Kerim, Yûnus Suresi 10:38
https://kuran.diyanet.gov.tr/mushaf/kuran-meal-2/10-suresi-38-ayet