sentences:  Not all souls come back to Earth with a corporeal body, as seen in "Ashes to Ashes," where the Mortician soul came back as a spirit since his body was cremated.As the souls that Sam is sent to apprehend have already died once (along with the fact that they have various paranormal abilities), an attempt to capture or even kill them by a mere mortal could prove almost impossible.The Devil provides Sam with vessels to help him do his work.