15 A single witness shall not suffice to convict a person of any crime or wrongdoing in connection with any offense that may be committed. Only on the evidence of two or three witnesses shall a charge be sustained. 16 If a malicious witness comes forward to accuse someone of wrongdoing, 17 then both parties to the dispute shall appear before the Lord, before the priests and the judges who are in office in those days, 18 and the judges shall make a thorough inquiry. If the witness is a false witness, having testified falsely against another, 19 then you shall do to the false witness just as the false witness had meant to do to the other. So you shall purge the evil from your midst.
Matthew Henry's Commentary on Deuteronomy 19:15-19
Commentary on Deuteronomy 19:15-21
(Read Deuteronomy 19:15-21)
Sentence should never be passed upon the testimony of one witness alone. A false witness should suffer the same punishment which he sought to have inflicted upon the person he accused. Nor could any law be more just. Let all Christians not only be cautious in bearing witness in public, but be careful not to join in private slanders; and let all whose consciences accuse them of crime, without delay flee for refuge to the hope set before them in Jesus Christ.