en_tn_condensed/lev/17/10.md

I will set my face against that person

This idiom means he "firmly decided." Alternate translation: "I have made up my mind to oppose that person" (See: rc://en/ta/man/translate/figs-idiom)

will set my face against

"will stare angrily at"

I will cut him off from among his people

A person being excluded from his community is spoken of as if he had been cut off from his people, as one would cut a piece of cloth or cut a branch from a tree. Alternate translation: "I will not permit that person to live among his people any longer" or "I will separate that person from his people" (See: rc://en/ta/man/translate/figs-metaphor)