There was a spiritual pain deep in his bones. Bones are the lasting record of our death. They are the last to disappear into dust. There are people who are trained to study dead bones. From your bones they can figure our whether you were male or female, how you lived, and how you died.
Bones are a universal symbol of death.
Deadly poisons are marked with the skull and crossbones. The same skull and crossbones used to be a popular headstone engraving in the 18th century. Skeleton costumes and bones abound at halloween, which at its best mocks death. When bones are uncovered in an unlikely spot, such as someone's backyard, we immediately suspect foul play. The bones tell us so.