23 “But if there is any further injury, then you shall appoint as a penalty life for life, 24 eye for eye, tooth for tooth, hand for hand, foot for foot, 25 burn for burn, wound for wound, bruise for bruise. Exod. 21:23–25, NASB
19 ‘If a man injures his neighbor, just as he has done, so it shall be done to him: 20 fracture for fracture, eye for eye, tooth for tooth; just as he has injured a man, so it shall be inflicted on him. 21 ‘Thus the one who kills an animal shall make it good, but the one who kills a man shall be put to death. Lev. 24:19–21, NASB
16 “If a malicious witness rises up against a man to accuse him of wrongdoing, 17 then both the men who have the dispute shall stand before the LORD, before the priests and the judges who will be in office in those days. 18 “The judges shall investigate thoroughly, and if the witness is a false witness and he has accused his brother falsely, 19 then you shall do to him just as he had intended to do to his brother. Thus you shall purge the evil from among you. 20 The rest will hear and be afraid, and will never again do such an evil thing among you. 21 Thus you shall not show pity: life for life, eye for eye, tooth for tooth, hand for hand, foot for foot. Deut. 19:16–21, NASB
In the passages above, Moses was giving the Law of God to the Israelites in their dealing with injuries done by one person on one or more people in a way that would limit retribution to that which was just. Its design was to insure that the punishment in civil cases fit the crime, but were never intended to sanction acts of personal retaliation. Therefore in Matthew 5:38-42 the Lord Jesus made no alteration to the true meaning of the law, but was merely explaining and affirming its true meaning.