﴿ وَإِذَا تُتْلَىٰ عَلَيْهِمْ ءَايَٰتُنَا قَالُوا۟ قَدْ سَمِعْنَا لَوْ نَشَآءُ لَقُلْنَا مِثْلَ هَٰذَآ ۙ إِنْ هَٰذَآ إِلَّآ أَسَٰطِيرُ ٱلْأَوَّلِينَ ﴾

“And whenever Our messages were conveyed to them, they would say, "We have heard [all this] before; if we wanted, we could certainly compose sayings like these [ourselves]: they are nothing but fables of ancient times!"”

Please check ayah 8:33 for complete tafsir.