After spending a long life the time for departure has come nigh. Perhaps it is the kindness of Allah that men get afflicted with disease and remain in this stage for some time before death. In this time they prepare themselves to meet their Creator. This is, perhaps, the reason that sudden deaths are considered a calamity. One who remains in the deathbed for a period, say a month, and doesn't awake to the fact and forgets to express penitence for his past sins before dying will be a very unfortunate person.