Surah Al-Kahf, Verse 6

Tafsir of 18:6

Do not feel sorry because the Idolators do not believe Allah consoles His Messenger for his sorrow فَلاَ تَذْهَبْ نَفْسُكَ عَلَيْهِمْ حَسَرَتٍ (So destroy not yourself in sorrow for them.) 35:8 وَلاَ تَحْزَنْ عَلَيْهِمْ (And grieve not over them.) 16:127 لَعَلَّكَ بَخِعٌ نَّفْسَكَ أَلاَّ يَكُونُواْ مُؤْمِنِينَ (It may be that you are going to kill yourself with grief, that they do not become believers.) 26:3 meaning, maybe you will destroy yourself with your grief over them. Allah says: فَلَعَلَّكَ بَخِعٌ نَّفْسَكَ عَلَى ءَاثَرِهِمْ إِن لَّمْ يُؤْمِنُواْ بِهَذَا الْحَدِيثِ (Perhaps, you would kill yourself in grief, over their footsteps, because they believe not in this narration.) meaning the Qur'an. أَسَفاً (in grief) Allah is saying, `do not destroy yourself with regret.' Qatadah said: "killing yourself with anger and grief over them." Mujahid said: "with anxiety." These are synonymous, so the meaning is: `Do not feel sorry for them, just convey the Message of Allah to them. Whoever goes the right way, then he goes the right way only for the benefit of himself.…

Source: Ibn Kathir (Abridged)