Not to belabor the questions that arise from the Cain & Abel story but when Cain slew Abel, he also slew all of Abel's descendants. We are told that both brothers, one a shepherd - the other a farmer, made sacrifices to God and Cain's sacrifice was found wanting. One can't help wondering at first, if God preferred lamb as opposed to salads (jest joking) or was it the attitude with which the sacrifice was given....begrudgingly or lovingly. Jewish apocrypha indicates that Cain's real motivation was that Abel got the sister to wife that Cain wanted. Either way, Cain is covetous/envious of Abel and his solution is to get rid of the competition. I can't get my head around trying or thinking you can fool/hide anything from God. And it occurs to me that you'd have to have a lot of arrogance that blinded you to imagine you could. There are so many aspects to this story. I think God wanted and gave Cain the chance to learn and repent from this but it doesn't seem he did.