"until you die and your body is put in the ground." In some cultures, they put the bodies of people who have died in a hole in the ground. Man's hard work does not end until the time of his death and burial.
# For dust you are, and to dust you will return
"I made you from soil, so your body will become soil again." Translate both occurrences of "dust" with the same word in order to show that man begins and ends in the same condition.