EXOD872 We favour kin over non-kin, friends over strangers, in-group over out-group. Without this, groups would not exist at all. And we need them, because we are social animals, not isolated individuals: "It is not good for man to be alone" (Gen. 2:18). Belonging to a group is essential to the sense of identity. On the other hand, a moral system that failed to acknowledge duties to strangers would simply generate endlessly warring tribes. Indeed, it seems to be implicit in the Torah that the Israelites experienced exile and enslavement in order to engrave this truth in collective memory: "You must not oppress strangers. You know what it feels like to be a stranger, for you yourselves were once strangers in the land of Egypt" [this verse]. [Continued at [[EXOD331]] Exodus 19:6 SACKS nation xxxi]