in the garden of eden god tells adam to not eat from the tree of knowledge, as he would die the same day. satan says, no you are not going to die, but you'll be just like god. he eats, he does not die the same day. but god is afraid that he could also eat fruit of the tree of life and be like him (actually: them), so he quickly bans him from eden...
I think he did die the same day, and every man (human) after him was born dead (spiritually separated from god). That's why Jesus said "let the dead bury the dead" D Dog