Tafsir of Al-Kahf 18:6

[6] He likens himself and them—when they turned away from him and did not believe in him, and the intensity of the anguish and sorrow that overcame him due to their turning away—to a man whose loved ones and dearest people have departed from him. He collapses in regret over their tracks, killing his soul with grief for them and yearning for their separation.

• "Bākhiʿan nafsaka" (killing yourself): It is read according to the original form (as an active participle) and as an idafa (genitive construction). It means: killing it and destroying it.
• Tense: It denotes the future for those who read in lam yuʾminū (if they do not believe), and the past for those who read an lam yuʾminū (meaning: li-an lam yuʾminū / because they did not believe).
• "Bi-hādhā al-ḥadīth" (in this discourse): Meaning the Qur'an.
• "Asafan" (out of sorrow): It is a mafʿūl lahu (causative object), meaning: out of excessive sadness. It is also permissible for it to be a ḥāl (state).
• Al-Asaf: The extreme of sadness and anger. It is said: a man is asif or asīf.

[7-11] "Indeed, We have made that which is on the earth adornment for it that We may test them [as to] which of them is best in deed. And indeed, We will make what is upon it a barren dust. Or have you thought that the companions of the Cave and the Inscription were, among Our signs, a wonder? When the youths retreated to the cave and said, 'Our Lord, grant us from Yourself mercy and prepare for us from our affair right guidance.' So We cast a cover over their ears in the cave for a number of years."