The concept of otherness was at the core of Israelite identity. Otherness is the core of holiness. The Hebrew vocabulary for holiness means to be set apart or to be distinct. While the idea has a moral dimension related to conduct, it is not intrinsically about morality. It is about distinction. Israel’s identification with Yahweh by virtue of his covenant with Abraham and the terms of the covenant at Sinai meant that, as Leviticus 19:2 concisely summarizes, Israelites were to be set apart (“holy”) as Yahweh was set apart (“holy”).
