Monotheism doesn’t necessarily mean sending all non-believers to hell

From Karen Armstrong’s A History of God: The 4,000-Year Quest of Judaism, Christianity and Islam:

The image of the olive tree in [certain Koranic] verses has been interpreted as an allusion to the continuity of revelation, which springs from one “root” and branches into a multifarious variety of religious experience that cannot be identified with or confined by any one particular tradition or locality: it is neither of the East nor the West