Deuteronomy 19:16-21

16If a false witness shall rise up against any man to testify against him that which is wrong;1 17Then both the men, between whom the controversy is, shall stand before the LORD, before the priests and the judges, who shall be in those days; 18And the judges shall make diligent inquisition: and, behold, if the witness is a false witness, and hath testified falsely against his brother; 19Then shall ye do to him, as he had thought to do to his brother: so shalt thou remove the evil from among you. 20And those who remain shall hear, and fear, and shall henceforth commit no more any such evil among you. 21And thy eye shall not pity; but life shall go for life, eye for eye, tooth for tooth, hand for hand, foot for foot.