Why does God say in the Old Testament “an eye for an eye” and then Christ said, No, that’s wrong; you must love one another?

First, let’s look at the specific scriptures in question. The phrase “an eye for an eye” originally comes from the Old Testament book of Exodus. God Himself is speaking to the nation of Israel, and He says, But if there is serious injury, you are to take life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burn for burn, wound for wound, bruise for bruise—God speaking, Exodus 21:23-25. In the context of His comments, He is addressing the specifics of a series of physical altercations that could possibly occur and what the appropriate justice would be for various outcomes of those altercations; in fact, in general God is speaking to the issue of justice and what that looks like. God expresses similar sentiments in the book of Leviticus where He says, If anyone takes the life of a human being, he must be put to death. Anyone who takes the life of someone’s animal must make restitution—life for life. If anyone injures his neighbor, whatever he has done must be done to him: fracture for fracture, eye for eye, tooth for tooth. As he has injured the other, so he is to be injured. Whoever kills an animal must make restitution, but whoever kills a man must be put to death—God speaking, Leviticus 24:17-21. The same principle comes into play in the case of perjury—lying—in the case o0f someone being accused of a crime. Moses explained it: One witness is not enough to convict a man accused of any crime or offense he may have committed. A matter must be established by the testimony of two or three witnesses. If a malicious witness takes the stand to accuse a man of a crime, the two 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. The judges must make a thorough investigation, and if the witness proves to be a liar, giving false testimony against his brother, then do to him as he intended to do to his brother. You must purge the evil from among you. The rest of the people will hear of this and be afraid, and never again will such an evil thing be done among you. Show no pity: life for life, eye for eye, tooth for tooth, hand for hand, foot for foot—Moses, Deuteronomy 19:15-21. Now, the New Testament scripture being referenced is spoken by Jesus Christ during the Sermon on the Mount where the concept of “an eye for an eye” is addressed in the context of a bigger principle. Jesus said, You have heard that it was said, ‘EYE FOR EYE, AND TOOTH FOR TOOTH.’ But I tell you, Do not resist an evil person. If someone strikes you on the right cheek, turn to him the other also. And if someone wants to sue you and take your tunic, let him have your cloak as well. If someone forces you to go one mile, go with him two miles. Give to the one who asks you, and do not turn away from the one who wants to borrow from you. You have heard that it was said, ‘LOVE YOUR NEIGHBOR and hate your enemy.’ But I tell you: Love your enemies and pray for those who persecute you, that you may be sons of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. If you love those who love you, what reward will you get? Are not even the tax collectors doing that? And if you greet only your brothers, what are you doing more than others? Do not even pagans do that? Be perfect, therefore, as your heavenly Father is perfect—Jesus Christ, the Sermon on the Mount, Matthew 5:38-48. Now, before anything else, it is important to make note of the fact that Jesus never says an “eye for an eye” is wrong; in other words, He is not correcting a mistake. If in fact God’s word is inerrant, Exodus and Leviticus and Deuteronomy are as completely correct as is Matthew and Mark and Romans. What Jesus did say earlier is this: Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them—Jesus Christ, the Sermon on the Mount, Matthew 5:17. And then, to amplify that thought, He said, I tell you the truth, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished—Jesus Christ, the Sermon on the Mount, Matthew 5:18. The Greek word for “fulfill” is PLEROO (play-ro^-o) and, by the way it is used here, it means to fulfill, bring to a full end, accomplish, complete. In this case, Jesus was going to accomplish full and complete obedience to the Law—something absolutely necessary if He was going to be a valid sacrifice for our sins—which also means that He was going to extend the Law to its full meaning (obedience in heart and mind as well as in action only). What He is also doing, and attempting to correct, is the wrong interpretations that had grown up over the centuries. In that context He is absolutely declaring those “laws” wrong—including the hypocritical Pharasaic legalism that had also come to power and the accompanying “traditions” of those leaders. But to the point of the question, there is no sense that Jesus is declaring anything in the Old Testament wrong or invalid. So then why wasn’t this concept, expressed as Jesus did it, found in the Old Testament as well as the New? We need to understand the intent of the Old Testament words to properly judge them. And, according to Christ, “an eye for an eye” and so forth was not given as a mandate for personal vengeance but rather as a judicial principle, lex talionis (the law of retaliation), guiding courts as they sought to dispense appropriate punishment—simply put, that the punishment fit the crime. Jesus’ point was that His disciples should not seek vengeance against even the most offensive blow. By extension, He is also spelling out what is most pleasing to the Father. When Christ talks about our being “sons of the Father,” He is referring to children being like their father. We are to reflect the Father in attitudes and in actions. No place is that more challenged than when someone in some way attacks us. Jesus is telling the crowd that day—and us—a better way, not one that gets rid of the Old Testament’s words, but rather brings them to a logical conclusion. All of the Old Testament law was meant to do the same thing that Jesus advocated here—make people become a reflection of the Father. That was the intent of the Ten Commandments. That was the intent of being a chosen people, that a reflection of the one true God was impact everybody contacted. That’s why Moses said, It is the Lord your God you must follow, and him you must revere. Keep his commands and obey him; serve him and hold fast to him—Moses, Deuteronomy 13:4. And Joshua, as he was dismissing the nation of Israel to their inheritance in the Promised Land at the end of his life, said, But be very careful to keep the commandment and the law that Moses the servant of the Lord gave you: to love the Lord your God, to walk in all his ways, to keep his commands, to hold fast to him and to serve him with all your heart and with all your soul”—Joshua 22:5. That message, and God’s intention, has never changed, from Old Testament to New.