"For your sake I hope heaven and hell are really there, but I wouldn't hold my breath"
I think what Isaac is really saying in this is that you can't just live your life in anticipation of an afterlife, or you miss out on actually living. the last part "but I wouldn't hold my breath" has a double meaning - he's saying that you can't count on there being an afterlife but also that you should go out and do something with yourself an make the most of what you have!
"For your sake I hope heaven and hell are really there, but I wouldn't hold my breath"
I think what Isaac is really saying in this is that you can't just live your life in anticipation of an afterlife, or you miss out on actually living. the last part "but I wouldn't hold my breath" has a double meaning - he's saying that you can't count on there being an afterlife but also that you should go out and do something with yourself an make the most of what you have!