Book excerpt: Many Christians and Jews believe that their faiths developed independently from each other, and that their religions are distinct, even antagonistic towards each other. A Portable God dramatically departs from the idea that the birth of Judaism and Christianity are two separate, unrelated events. Judaism and Christianity's origins are not seen as following a linear, chronological process that places the Israelites in the beginning, followed by the Jews, and finally the Christians. On the contrary, A Portable God shows that both Judaism and Christianity emerge from the same religious tradition--that of ancient Israel--at the same time. By telling the common story of Jewish and Christian origins, A Portable God shows Jews and Christians as siblings, rather than as parent and child, showing that the similarities between Judaism and Christianity far outweigh their differences, ultimately fostering appreciation for the shared heritage of Judaism and Christianity.