If the bible says your body is god's holy temple, then why does every body die and rot away?

Ok, this is something I never understood. I've been told by christians that it is a sin to damage the body because it's god's temple. When you die, though, your body decays and rots away and is eaten by maggots. Why would the human body be considered holy or important if it only lasts temporarily for a short time? At least very short compared to eternity.