i did bring up the good old mixed-fabrics bit : i need to memorise the chapter and line numbers of that. there's what i consider a perfectly good answer to this in mainstream christianity, which is to note that jesus brought a new covenant. (mind, I don't quite understand what criteria is used to determine which bits of the old covenant lurk around.) similarly i would have taken "it was all part of god's unknowable plan" as an answer for "why hold someone morally responsible for an action [eating an apple] when they did not yet have knowledge of good and evil and understand morality".