Which Old Testament laws still apply to Christians today?

Open the book of Leviticus and you will find commands about sacrifices, priestly garments, dietary restrictions, and mixed fabrics sitting right alongside commands against murder, theft, and dishonesty. Naturally, readers ask why Christians eat shellfish and wear blended fabrics without a second thought, yet still consider murder and adultery seriously wrong. The answer is not arbitrary; it flows from how the New Testament itself treats different categories within the Old Testament law.

Working through this question carefully protects Christians from two opposite errors, ignoring God's unchanging moral standards altogether, or imposing on believers today obligations that Scripture itself says have been fulfilled and set aside in Christ.

Many theologians distinguish three categories within Old Testament law. Moral law reflects God's unchanging character, commands like do not murder, do not steal, do not bear false witness (Exodus 20:1-17), and these remain binding because they describe who God is, not merely what ancient Israel needed. Civil law governed Israel's life as a specific nation under a theocratic government, penalties, property regulations, and social structures suited to a particular time and place. Ceremonial law governed Israel's worship, sacrifices, priestly duties, festivals, and purity codes.

This framework, while not laid out explicitly as three labeled categories in Scripture, is a genuinely useful tool because the New Testament treats these categories differently, reaffirming the moral law while explicitly setting aside the ceremonial system (Hebrews 10:1) and no longer binding Christians to Israel's civil code as a nation-state (Ephesians 2:14-15).

The clearest test for whether an Old Testament law still applies is whether the New Testament repeats or reaffirms it. Nine of the Ten Commandments are directly repeated as binding for Christians (only the Sabbath command is treated differently, discussed elsewhere). Paul lists commands against adultery, murder, theft, and covetousness, then sums them up, again, in the command to love your neighbor as yourself (Romans 13:9-10). Jesus Himself identifies loving God and loving neighbor as the commands on which all the Law and the Prophets depend (Matthew 22:37-40).

Beyond the Ten Commandments, principles of justice, honesty, generosity to the poor, sexual purity, and care for the vulnerable, all rooted in Old Testament law, are consistently reaffirmed throughout the New Testament epistles. Paul, for instance, grounds his instruction that workers deserve fair wages directly in an Old Testament law about not muzzling an ox while it treads out grain, applying its underlying principle of just compensation to a New Testament setting (1 Corinthians 9:9-10; Deuteronomy 25:4). This shows that even laws which seem, on the surface, to be narrowly agricultural often carry a moral principle the New Testament explicitly carries forward.

The sacrificial and priestly system finds its fulfillment in Christ, who offered Himself once for all as the final sacrifice for sin, making the old system's shadow give way to its substance (Hebrews 10:1-14). The Jerusalem council in Acts 15 explicitly wrestled with whether Gentile believers must be circumcised and keep the full Mosaic law, and concluded they should not, asking only that they abstain from a short list of practices for the sake of fellowship with Jewish believers (Acts 15:19-29).

Dietary laws distinguishing clean and unclean foods were declared fulfilled when God gave Peter a vision affirming that what God has made clean, no longer call common (Acts 10:15). These ceremonial markers set Israel apart as a distinct nation; in Christ, that separation between Jew and Gentile has been broken down (Ephesians 2:14-15).

Festivals such as Passover, the Feast of Weeks, and the Day of Atonement likewise find their fulfillment in Christ rather than their ongoing observance as required practice. Paul explicitly calls Christ our Passover lamb, sacrificed for us (1 Corinthians 5:7), showing that the festival's entire meaning has been gathered up and completed in the cross. Christians are free to appreciate these festivals as rich, instructive pictures of what Christ accomplished without treating their observance as a continuing obligation.

A practical rule of thumb: when in doubt, check whether a command is grounded in God's unchanging character (likely still binding), whether it regulated Israel's specific national life (likely not binding in the same form), or whether it pointed toward Christ's sacrificial work (fulfilled, not repeated). The moral core of Leviticus 19:18, love your neighbor as yourself, still governs Christian ethics precisely because Jesus quoted it as foundational.

This approach keeps Christians from either dismissing the Old Testament as irrelevant or binding believers to obligations Christ has already fulfilled. The law was never the final word; it was always meant to lead to Him, and in Him, its abiding moral core lives on in the hearts of His people (Jeremiah 31:33).