Surah Al-Kahf Ayahs #78 Translated in English

So they set out, until when they met a boy, he [i.e., al-Khiḍr] killed him. [Moses] said, "Have you killed a pure soul for other than [having killed] a soul? You have certainly done a deplorable thing."

[Al-Khiḍr] said, "Did I not tell you that with me you would never be able to have patience?"

[Moses] said, "If I should ask you about anything after this, then do not keep me as a companion. You have obtained from me an excuse."

So they set out, until when they came to the people of a town, they asked its people for food, but they refused to offer them hospitality. And they found therein a wall about to collapse, so he [i.e., al-Khiḍr] restored it. [Moses] said, "If you wished, you could have taken for it a payment."

[Al-Khiḍr] said, "This is parting between me and you. I will inform you of the interpretation of that about which you could not have patience.