The Story of killing the Boy
(Then they both proceeded,) means, after the first incident,
(till they met a boy, and he (Khidr) killed him.) It has been stated previously that this boy was playing with other boys in one of the towns, and that Al-Khidr deliberately singled him out. He was the finest and most handsome of them all, and Al-Khidr killed him. When Musa, peace be upon him, saw that he denounced him even more fervently than in the first case, and said hastily:
(Have you killed an innocent person) meaning, a young person who had not yet committed any sin or done anything wrong, yet you killed him
(without Nafs) with no reason for killing him.
(Verily, you have committed a thing Nukr!) meaning, something that is clearly evil.
(He said: “Did I not tell you that you can have no patience with me”) Once again, Al-Khidr reiterates the condition set in the first place, so Musa says to him:
(If I ask you anything after this,) meaning, `if I object to anything else you do after this,’
(keep me not in your company, you have received an excuse from me.) `you have accepted my apology twice.’ Ibn Jarir narrated from Ibn `Abbas that Ubayy bin Ka`b said: “Whenever the Prophet mentioned anyone, he would pray for himself first. One day he said:
(May the mercy of Allah be upon us and upon Musa. If he had stayed with his companion he would have seen wonders, but he said, (`If I ask you anything after this, keep me not in your company, you have received an excuse from me.’))”