﴿ وَإِن يَكَادُ ٱلَّذِينَ كَفَرُوا۟ لَيُزْلِقُونَكَ بِأَبْصَٰرِهِمْ لَمَّا سَمِعُوا۟ ٱلذِّكْرَ وَيَقُولُونَ إِنَّهُۥ لَمَجْنُونٌۭ ﴾

“Hence, [be patient,] even though they who are bent on denying the truth would all but kill thee with their eyes whenever they hear this reminder, and [though] they say, "[As for Muhammad,] behold, most surely he is a madman!"”

Please check ayah 68:52 for complete tafsir.