Full Idea
Belief in resurrection and the afterlife was the main distinguishing mark of Pharisaism, and thus fundamental of rabbinic Judaism.
Gist of Idea
The main doctrine of the Pharisees was belief in resurrection and the afterlife
Source
Paul Johnson (The History of the Jews [1987], Pt II)
Book Reference
Johnson,Paul: 'A History of the Jews' [Phoenix 1993], p.161
A Reaction
Belief in an afterlife seems to go back to the Egyptians, but this development in Judaism was obviously very influential, even among early Christians, who initially seem to have only believed in resurrection of the body.