en_tn/deu/19/16.md

Suppose that

"When" or "If"

an unrighteous witness

"a witness who intends to harm someone else"

rises up against any man to testify against him of wrongdoing

Here "rise up" means to stand up in court and speak against someone to a judge. AT: "tells the judge that a man sinned in order to get the man in trouble" or "tells the judge that a man sinned, so the judge will punish him" (See: rc://en/ta/man/translate/figs-idiom)