en_tn/jas/04/12.md

Only one is the lawgiver and judge

This refers to God. "God is the only one who gives laws and judges people"

Who are you, you who judge your neighbor?

This is a rhetorical question James uses to scold his audience. This can be expressed as a statement. Alternate translation: "You are just a human and cannot judge another human." (See: rc://en/ta/man/jit/figs-rquestion)