Death was given to us because of Adam’s sin. I know there are people who have difficulty with this. They wonder why Adam’s sin is imputed or reckoned or added to their account. But in truth Adam is the federal head of the entire human race. And with his sin has come death to the entire human race.
Now if you are not careful you will think of a natural body as a physical body and a spiritual body as a non-physical body. But that is entirely the wrong idea. A spiritual body is a real body. But it rightfully belongs to the age to come, that is where it functions.