Deuteronomy 19:15-21

“A single witness shall not suffice against a person for any crime or for any wrong in connection with any offense that he has committed. Only on the evidence of two witnesses or of three witnesses shall a charge be established. If a malicious witness arises to accuse a person of wrongdoing, then both parties to the dispute shall appear before the LORD, before the priests and the judges who are in office in those days. The judges shall inquire diligently, and if the witness is a false witness and has accused his brother falsely, then you shall do to him as he had meant to do to his brother. So you shall purge the evil from your midst. And the rest shall hear and fear, and shall never again commit any such evil among you. Your eye shall not pity. It shall be life for life, eye for eye, tooth for tooth, hand for hand, foot for foot.