Larry Hurtado in Slate:
The idea of a real, personal resurrection—meaning a new bodily existence of individuals after death, in one way or another—did not originate with Christianity or with claims about Jesus. Instead, it seems to be first clearly reflected in Jewish texts dated to sometime in the second century B.C., such as the biblical book of Daniel 12:2. At the time, it was a genuinely innovative idea. (Alan Segal’s book Life After Death gives an expansive discussion of the origins of the idea of resurrection.) Many peoples of the ancient world hoped for one or another sort of eternal life, but it was usually thought of as a kind of bodiless existence of soul or spirit set in realms of the dead that might or might not be happy, pleasant places. In still other expectations, death might bring a merging of individuals with some ocean of being, like a drop of water falling into the sea.
The ancient Jewish and early Christian idea of personal resurrection represented a new emphasis on individuals and the importance of embodied existence beyond the mere survival or enhancement of the soul, although there was debate about the precise nature of the post-resurrection body. Some seem to have supposed it would be a new body of flesh and bones, closely linked to the corpse in the grave but not liable to decay or death. Others imagined a body more like that of an angel. But whatever its precise nature, the hope of resurrection reflected a strongly holistic view of the person as requiring some sort of body to be complete.