We have heard about the Fountain of Youth from the beginning of time
Even the Book of Genesis said that , had not mankind been so
arrogant , we would be living forever.
Death was the penalty for being mortals (mortals? short lives?)
I will abide with the entrance of the Son of God into our humanity
and the lasting effects of living forever, but not in this shell
of a body. Someone "our spirit" will live forever.
When a human "expires" his spirit leaves the body
So when you look at your dead mother, child or spouse
you can see that there is no longer any spirit in that
shell of a corpse. Even animals mourn for the lifeless
body of some other animal they were friends with.
At some point, maybe days, they accept that that is
no longer who they loved
That is why I like the string theory and multiple
dimensions. We can see elaborate preparations for
the after life in every culture