In ancient Egypt, grave robbing was considered the worse crime anyone could commit.
Grave robbers were in a hurry when they broke into a tomb to steal whatever they could find that had value. They wanted to grab and get away. The punishment for grave robbing was a horrible and hideous death. No grave robber wanted to stick around. Because they were in a hurry, they often broke the cartouche, the name plate on the coffin, when they opened the coffin. They ripped the fabric around the mummy, the preserved body, looking for treasure buried in the wrappings. This put the Ba and Ka at great risk.
The ancient Egyptians believed that everyone had a soul that split into two parts after you died. One part, the Ba, watched over your living family. The other, the Ka, enjoyed life in the Land of Two Fields. At night, both the Ba and the Ka returned to your tomb.
But if something happened to your tomb, if your preserved body was damaged or your name was lost, the Ba and Ka would get lost. They couldn't find you. They would not be able return to the tomb. If that happened, you were lost forever. You disappeared. And your afterlife would be over.
You can see why grave robbing, to the ancient Egyptians, was such a serious crime. They were stealing your eternity.