The Jewish Nation heard the first two commandments from Hashem directly. The power of this experience caused them to die. Hashem had to revive them from the dead.

The purpose of this was to trade in our physical, finite existence for a new type of body. A body which has Torah as its DNA. This body is bound with Hashem and lives forever.

Death is only final for a finite body. One who is willing to give up ones life for Hashem, has traded in one's physical body for an eternal infinite existence. Such a person can never truly die!