Death & Janazah

Question In Mishkat (pg 26, Pakistan copy, the first hadith of the third section) it is mentioned that the grave of Sa’d radiallahu anho was closed upon him. Is there any reason for this, or does this mean that everyones grave closes upon him

Question Please cite some important du’as taught by Rasulullah (sallallahu’alaihi wasallam) for protection against a painful death.