Yahweh speaks of preventing the people from becoming unclean as if it were keeping the people at a safe distance from uncleanness. The abstract noun "uncleanness" can be stated as "unclean." Alternate translation: "This is how you must prevent the people of Israel from becoming unclean" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-abstractnouns]])
People whom other people may not touch and who are not acceptable for God's purposes are spoken of as if they were physically unclean. (See: [[rc://en/ta/man/translate/figs-metaphor]])