فَٱنطَلَقَا حَتَّىٰٓ إِذَا لَقِيَا غُلَـٰمًا فَقَتَلَهُۥ قَالَ أَقَتَلْتَ نَفْسًا زَكِيَّةًۢ بِغَيْرِ نَفْسٍ لَّقَدْ جِئْتَ شَيْـًٔا نُّكْرًا
Fa i n t alaq a h att a i tha laqiy a ghul a man faqatalahu q a la aqatalta nafsan zakiyyatan bighayri nafsin laqad jita shayan nukr a n And so the two went on, till, when they met a young man, [the sage] slew him - [whereupon Moses] exclaimed: "Hast thou slain an innocent human being without [his having taken] another man's life? Indeed, thou hast done a terrible thing!"
 - Mohammad Asad
So they journeyed on until they met a boy, and Khizr slew him. Musa said: "You have killed an innocent person though he had killed nobody. Surely you have done a horrible deed!"
 - Muhammad Farooq-i-Azam Malik
So they proceeded until they came across a boy, and the man killed him. Moses protested, 'Have you killed an innocent soul, who killed no one? You have certainly done a horrible thing.'
 - Mustafa Khattab
So the twain journeyed on till, when they met a lad, he slew him. (Moses) said: What! Hast thou slain an innocent soul who hath slain no man? Verily thou hast done a horrid thing.
 - Marmaduke Pickthall
Then they proceeded: until when they met a young man he slew him. Moses said: "Hast thou slain an innocent person who had slain none? Truly a foul (unheard-of) thing hast thou done!" 2418
 - Abdullah Yusuf Ali