Incase you don't know yet, Death is being away from God, not being able to be close to God.
After our bodies die, we have two choises to spend the rest of our "live"
Or we go to hell(There where God is not, a place of eternal neverending darkness) and are there to suffer forever, or we go to heaven, which is life beacouse we are then close to God.
In other words, Going to hell equals death.
Beacouse Jesus took up all the sins of the world upon himself, God couldn't stand being with him anymore(There where is sin God cannot be) and he cried out on the cross "God my god, why have you forsaken me".
He went to death becouse of this sin, but he conquered death and by winning that battle he has set us free from sin. by that he has bridged the gap that was between God and humankind.