Supporters of Zionism, atheist and religious alike, generally rely on two points of religious dogma to validate the occupation of Palestine: the idea that followers of Judaism are “God’s chosen people”, to the exclusion of all others; and the idea that God “gave” the “children of Abraham” all the land between the Nile and the Euphrates rivers. The borders are vaguely and contradictorily defined in multiple places in the Torah (Old Testament).
The concept of “Eretz Israel” (Hebrew “Land of Israel”, with the connotation of expansionism that “Greater Israel” implies in English) is based on a merger of religious fundamentalism and modern political ethno-nationalism, whereby ancient texts are used to justify a modern military expansionist state.