﴿ وَقَالُوا۟ يَٰٓأَيُّهَا ٱلَّذِى نُزِّلَ عَلَيْهِ ٱلذِّكْرُ إِنَّكَ لَمَجْنُونٌۭ ﴾

“And yet, they [who deny the truth] say: "O thou unto whom this reminder has [allegedly] been bestowed from on high: verily, thou art mad!”

Please check ayah 15:9 for complete tafsir.