 Ritual purity is essential for an Israelite to be able to approach Yahweh and remain part of the community.Uncleanliness threatens holiness; Chapters 11–15 review the various causes of uncleanliness and describe the rituals which will restore cleanliness; one is to maintain cleanliness through observation of the rules on sexual behaviour, family relations, land ownership, worship, sacrifice, and observance of holy days.Yahweh dwells with Israel in the holy of holies.