Qur'ān 18:6 · Al-Kahf (الكهف)

فَلَعَلَّكَ بَـٰخِعٌۭ نَّفْسَكَ عَلَىٰٓ ءَاثَـٰرِهِمْ إِن لَّمْ يُؤْمِنُوا۟ بِهَـٰذَا ٱلْحَدِيثِ أَسَفًا

Then perhaps you would kill yourself through grief over them, [O Muhammad], if they do not believe in this message, [and] out of sorrow.