Deuteronomy 19:15-21

15One witness is not enough to convict anyone accused of any crime or offense they may have committed. A matter must be established by the testimony of two or three witnesses. 16If a malicious witness takes the stand to accuse someone of a crime, 17the two people involved in the dispute must stand in the presence of the Lord before the priests and the judges who are in office at the time. 18The judges must make a thorough investigation, and if the witness proves to be a liar, giving false testimony against a fellow Israelite, 19then do to the false witness as that witness intended to do to the other party. You must purge the evil from among you. 20The rest of the people will hear of this and be afraid, and never again will such an evil thing be done among you. 21Show no pity: life for life, eye for eye, tooth for tooth, hand for hand, foot for foot.