Making sense of the Mosaic Law in the current age is not an easy task. While there are many opinions, one that is more common across several different traditions is to treat the law in a threefold way. That is, the commands of the Old Testament are grouped together into moral, civil, and ceremonial. One can see that the law prohibiting the eating of shellfish or fish lacking scales (Lev 11:10) is a ceremonial law, as are the regulations governing the sacrificial offerings in the first six chapters of Leviticus. One could say that the cities of refuge, outlined in Numbers 35 deal with civil matters, for they stipulate a matter of administering justice in Israel.
When it comes to moral law, it becomes more difficult. Are the laws governing various aspects of life in the holiness code of Leviticus 18-22 not moral?
You shall not oppress your neighbor or rob him. The wages of a hired worker shall not remain with you all night until the morning. You shall not curse the deaf or put a stumbling block before the blind, but you shall fear your God: I am the Lord. (Lev. 19:13-14)
Why was Israel prohibited from doing these things? Because they were wrong, immoral. Can we make such a clean division between moral, civil, and ceremonial as most people assume? Peter Gentry and Stephen Wellum observe the following:
It is common to categorize and classify the laws as (a) moral, (b) civil, and (c) ceremonial, but this classification is foreign to the material and imposed upon it from the outside rather than arising from the material and being clearly marked by the literary structure of the text. In fact, the ceremonial, civil, and moral laws are all mixed together, not only in the Judgments or ordinances but in the Ten Words as well (the Sabbath may be properly classified as ceremonial).”
While it’s possible to assign the Mosaic laws to various aspects of life in Israel, this becomes quite problematic when the three categories are used as a foundation for the Mosaic law in the lives of believers today. In other words, we can catalog the laws according to these divisions, but we cannot use those divisions to say that two out three are gone, but the third remains, and Christians are obligated to obey these laws.
This is important because when it comes to moral law, the Ten Commandments are for many, the shorthand for this. However, we’ve seen this to be incorrect on a couple of points. Moral laws certainly exist outside of the Ten, and even within them, the Fourth Commandment is regarded as ceremonial by almost everyone. Even if it’s not, it’s treated with such flexibility and looseness that those who say they are keeping it are in fact not doing so. (The Sabbath is Saturday, not Sunday and if you’ve ever tidied up the house on Saturday, you’ve broken the Sabbath.)
An objection one often hears is that “Nine of the Ten Commandments are repeated in the New Testament.” Indeed, they are, but the question is how they are. Consider Romans 13:8-10:
Owe no one anything, except to love each other, for the one who loves another has fulfilled the law. For the commandments, “You shall not commit adultery, You shall not murder, You shall not steal, You shall not covet,” and any other commandment, are summed up in this word: “You shall love your neighbor as yourself.” Love does no wrong to a neighbor; therefore love is the fulfilling of the law.
Paul’s citing of the commandments is almost parenthetical here. His true interest is in promoting love among these believers. Love, he says, is the fulfillment of the law. But note what is not here. He does not say “You must keep these commandments.” They are not inconsistent with his own teaching, but love goes beyond this. I could keep the law, but yet still not love. Paul most commonly uses the commandments as illustrations, as wisdom, but he never says believers must obey the Ten Commandments.
Paul also quotes the fifth commandment to the Ephesian church: “‘Honor your father and mother’ (this is the first commandment with a promise), ‘that it may go well with you and that you may live long in the land.’” It is important to note that this citation comes after his own command to these believers: “Children, obey your parents in the Lord, for this is right” (Eph 6:1). In other words, Paul does not begin with the Mosaic commandment, but rather with his own apostolic instruction to the church. He quotes the fifth commandment to demonstrate that his own application is consistent with what the Decalogue requires, but goes beyond it.
Everywhere in the New Testament, the law is treated as a unit, and indivisible. Paul speaks only of law, not of moral, ceremonial, or civil. And indeed when he makes his most definitive statements about believers released from obligation to law, he draws his examples from those very portions styled “the moral law.” In Romans 7, Paul quotes the tenth commandment, “You shall not covet,” and goes on to say, “But sin, seizing an opportunity through the commandment, produced in me all kinds of covetousness.”
Is Paul speaking of something civil or ceremonial? Clearly not. The Tenth Commandment is part of the “moral law,” yet just a few verses before this Paul has said “Likewise, my brothers, you also have died to the law through the body of Christ.” (Rom. 7:4) We can only conclude that when Paul says we have died to the law, he means all of it, including the Ten Commandments. Christian holiness is measured on a different axis from the Mosaic Law. It is conformity to Christ, walking by the Spirit, and indeed, being free from the dominion of sin because we are not under the law. (Rom 6:14) For a fuller discussion, see If One Uses It Lawfully: The Law of Moses and the Christian Life.
 Gentry, Peter John, and Stephen J. Wellum. Kingdom through Covenant: A Biblical-Theological Understanding of the Covenants (Wheaton, IL: Crossway, 2012), p. 384.