Some Christians ask: "If the Law is done away, how do we know what God expects of us, and what should our moral guidelines be for living a Christian life?"
The question comes partly because we don’t precisely and correctly define our terms. When Jesus or Paul speak of "the law," they are often referring to the commandments set down in the old covenant. Jewish rabbis identified 613 such laws. "The Law" could also refer to the entire Old Testament, or to the teachings of the Law and the Prophets, two of the three sections of the Jewish Holy Scriptures. "The Law" could also refer more precisely to the first five books of the Old Testament.
We could become even more specific and say that "the Law" refers to all the commandments and regulations found between Exodus 20:1 and Deuteronomy 34:12. (Circumcision was given earlier in Genesis 17:9-14, and then incorporated into the Law of Moses, as Leviticus 12:3 shows.) This would include the Ten Commandments, which serve as a kind of introduction and summary of Israel’s obligations under the old covenant.
There is nothing special about the Ten Commandments as individual laws. The ten precepts found there are also found in the rest of the Law of Moses, where they are explained and expounded in greater detail. On the other hand, the Ten Commandments lack some important principles found in the rest of the Mosaic Law. For example, the two "great commandments" of loving God above all (Deuteronomy 6:5) and one’s neighbor as oneself (Leviticus 19:18) are not part of the Ten Commandments.
The Israelites would have been able to fulfill the terms of the old covenant even if they didn’t have the Ten Commandments, but they could not do so if those were the only commandments they had. The point is that the Ten Commandments must be put in their proper perspective. By themselves, they did not comprise the definitive statement of what constituted a covenantal relationship between God and his people Israel. They certainly do not represent the best of the old covenant, and certainly not of the new, as some Christians wrongly assume. (Perhaps they have achieved their near mythic status among some Christians because they are concise – they have "sound bite" value.)
The concept of fulfilling the "terms" of the covenant may need a brief explanation. Both the old and new covenants are based on God’s grace. The "terms" of either covenant set down in the Law of Moses or "law of Christ" are the expected responses to God’s grace. God’s grace is given by him as a free gift, and is not earned by this expected response of obedience and faithfulness.
"The Law" or "God’s Law," when this is a reference to the complete old covenant legal system, was considered as a single entity or one whole law. New Testament writers do not break up the Law of Moses into distinct categories when they speak of it. Yet, there is nothing wrong in doing so in order to help us understand what the Law was and what its relationship to the Christian might be.
The Mosaic Law contained several categories of law, including ceremonial, sacrificial, civil and moral-spiritual regulations. An example of a ceremonial law would be the regulation that required a woman to be "unclean" for a certain period of time after giving birth. A sacrificial law might involve the sacrificing of an animal, as in the burnt offering. An example of a civil statute would be the regulation that a Hebrew slave or servant was to serve six years and be freed in the seventh year without any payment to the owner. A moral-spiritual principle would be Leviticus 19:18 that commanded Israelites to love their neighbor as themselves.
Each of these categories of law is different from the other, and some do not have direct application to Christians. For example, Christian men do not need to be physically circumcised to be within a new covenant relationship with God. Christian women are not ceremonially unclean after giving birth. This leads to one important conclusion. If we want to ask about specific commandments contained in the Law of Moses (including the Ten Commandments) we always have to ask: Of all the laws God gave, which ones must Christians also keep?
The correct way to understand the Law of Moses is that it was an old covenant specific code, and has no jurisdiction upon Christians. The Mosaic Law defined the terms of the old covenant. But Christians are not under the old covenant. They are people of the new covenant and the "law of Christ" (Galatians 6:2). The Law of Moses is "done away" as far as Christians are concerned, and it is replaced by the "law of Christ."
Of course, there may be commandments in both the Law of Moses and the "law of Christ" that are similar or the same, and they would apply to both old covenant Israelites and new covenant Christians. But this does not mean all the old covenant laws apply to Christians. We must know how to choose between them, and on what basis to make this choice.
Perhaps an example will illustrate. If you live in California you must obey the regulations of the California Motor Vehicle Code when you drive your car. If you move to New York, you no longer need to obey this code but must now be in
compliance with the New York State driving code. You are no longer a Californian but a New Yorker. Of course, both codes have many of the same laws, but they will also have some different regulations. Just because the New York code contains some of the same regulations as the California code does not mean you must keep those regulations in the California code that do not appear in the regulation book for New York. Neither are you under the jurisdiction of the California motor vehicles code, because you have moved to a new state.
In the same way, Christians are not under the old covenant Mosaic Law because they are new covenant Christians living under the "law of Christ." Just because some individual regulations of the Mosaic Law apply to Christians, does not mean they all do, regardless of whether they are in the Ten Commandments or the Law of Moses proper. How do we know which laws we must obey? The answer is simple. The New Testament tells us which ones we should comply with.
We can find out which laws apply to us by looking at the "sin and virtue" lists that are found in various parts of the New Testament. Let’s look at Galatians 5:14-25 as an example. This passage of Scripture begins by telling us that we should love our neighbor as our self—one of the two "great commandments" of the Law of Moses.
In verses 19-21, the apostle Paul lists a number of "acts of the sinful nature," which he says should be "obvious" to a Christian in that they violate God’s purpose for us. He lists "Thou shall nots" against sexual immorality, impurity and debauchery, idolatry and witchcraft, hatred, discord, jealousy, fits of rage, selfish ambition, dissentions, factions, envy, drunkenness, orgies and other sins that are "like" these. We could probably think of a number of similar sins and add them to the list. One of these would be adultery. Another would be murder. While these are mentioned in the Ten Commandments and the rest of the Mosaic Law, Christians do not need to rely on their being mentioned in the old covenant. The New Testament "law of Christ" tells us what laws Christians should obey.
Paul’s "Thou shalls" are stated in verses 22 and 23, and include love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control. Paul concludes by saying: "Those who belong to Christ Jesus have crucified the sinful nature with its passions and desires. Since we live by the Spirit, let us keep in step with the Spirit" (verses 24-25). He wraps up the discussion by relating what he said in verses 19-23 to the fulfilling of "the law of Christ" (6:2). The Ten Commandments do not teach these vital principles in a direct way.
Even by itself, this passage in Galatians would provide a thorough moral guide for our lives and tell us what obedience to God means. But, as mentioned earlier, the New Testament is filled with such instruction. Another example is the book of James, which also tells us how to fulfill God’s law in terms of loving our neighbor as ourselves (James 2:8). Again, here is another reference to one of the two "great laws" of the Law of Moses. Some elements of James’ moral code include: looking after orphans and widows, keeping oneself from being polluted by the world, not showing favoritism, taming the tongue and not indulging in slander or gossip, avoiding envy and selfish ambition, not being a "friend of the world," resisting the devil, praying in faith and being patient.
If you add all the principles and commandments in the New Testament about how Christians are to live, you will have a rather complete understanding of the "law of Christ." This will provide a more than adequate moral and spiritual guide to help us understand how to love God and human beings.
In conclusion, the New Testament gives us the moral and spiritual guide we need in order to serve God. What we should notice about this guide is that it nowhere commands Christians to keep the ceremonial and sacrificial regulations that are limited to the old covenant Law of Moses. For example, there is no New Testament command for Christians to keep the weekly or annual Sabbaths as "holy time." These were part of the old covenant Law of Moses, which is "done away," replaced by the New Testament and new covenant "law of Christ."
A related article: The role of the decalogue in Christian ethics