The Greek that is translated as “I have kept all these since my youth” or similar in English is translated in Githabul as “When I was a boy I heard [obeyed] all these things, I have never been disobedient [not hearing] to what you have said.” It was not possible to say “I have done all these things,” since that would have meant he killed, committed adultery, stole, etc. (Source: B. Moore / G. Turner in Notes on Translation 1967, p. 1ff.)