en_tn_lite_do_not_use/mat/18/16.md

so that by the mouth of two or three witnesses every word might be confirmed

Here "mouth" and "word" refer to what a person says. This can be stated in active form. Alternate translation: "so that two or three witnesses may say that what you say about your brother is true" (See: rc://en/ta/man/jit/figs-metonymy and rc://en/ta/man/jit/figs-activepassive)