It often comes up in conversations about sexuality. A Christian might cite an Old Testament law—perhaps from Leviticus—concerning sexual sin, only to be met with the retort: “Why do you only observe some Old Testament laws? Aren’t you being selective? If you’re going to follow the Old Testament, what about shellfish, mixed fabrics, and Sabbath observance?”
This objection isn’t new. In fact, it goes back to some of the earliest Christian apologetics. Around the year 150 A.D., a Christian named Justin Martyr wrote a dialogue with a Jewish man named Trypho. In it, Trypho asks a similar series of questions: You Christians claim to be pious and better than others, yet you don’t keep the Sabbath, you don’t circumcise your children, and you don’t observe the Jewish festivals. How can you expect anything good from God if you won’t obey his commandments?
Trypho’s question and the modern objection both boil down to the same issue: Are Christians inconsistent in how they apply Old Testament law?
Justin Martyr’s response in the Dialogue with Trypho offers a helpful framework for answering this objection—one that still applies today. Here are three key insights from Justin’s reply that every Christian should understand.
1. There Are Different Types of Old Testament Law
Justin carefully distinguishes between different kinds of laws in the Old Testament, a distinction that many people—both Christians and non-Christians—fail to make.
- Moral Laws are universal, unchanging expressions of God’s character. These include the Ten Commandments and other commands that reflect God’s justice, holiness, and love. Moral laws are binding for all people, in all places, at all times. They are reiterated in the New Testament (see Romans 13:8–10), and according to Romans 2:15, are written on the hearts of all people.
- Ceremonial Laws were specific to Israel’s worship under the old covenant. These included sacrifices, circumcision, temple rituals, dietary restrictions, and purity codes (like not mixing fabrics or shaving the sides of the beard). These laws were meant to point forward to Christ and set Israel apart from the surrounding nations. But once Christ came, these laws were fulfilled and no longer required (see Hebrews 10:1–14; Colossians 2:16–17).
- Civil Laws governed the day-to-day life of ancient Israel as a theocratic nation. These included judicial penalties, land laws, and other regulations unique to that society. While they reflect God’s justice, they are not directly binding on nations today.
This distinction helps us understand why Christians affirm some Old Testament laws (like prohibitions on adultery or murder) while no longer keeping others (like dietary restrictions or ceremonial rituals). Jesus himself affirms this when he says in Matthew 5:17 that he came not to abolish the Law but to fulfill it. That fulfillment changes how we relate to ceremonial laws today.
As Justin Martyr puts it, Christ is “the new law, and the new covenant,” given not only to Israel but to people from every nation who hope in God. Because Jesus has fulfilled the whole law, Christians now live under a new covenant, not the old one. And that means that we no longer need to observe Israel’s former ceremonial and civil laws.
2. Righteousness Has Never Come Through Religious Observance
Justin also makes an important theological point: ceremonial laws were never the means of salvation. He appeals to the example of Enoch, who “was well-pleasing to God, though he was not circumcised.” He also points to Abraham, who was declared righteous before the law was given, and who did not observe the Jewish festivals. “All these righteous men,” Justin writes, “though they kept no Sabbaths, were pleasing to God.”
This is consistent with the apostle Paul’s argument in Romans and Galatians. Righteousness has always come through faith, not works of the law. Paul writes in Galatians 3:6–7, “Just as Abraham ‘believed God, and it was counted to him as righteousness,’ know then that it is those of faith who are the sons of Abraham.”
In other words, even under the old covenant, the ceremonial laws were never intended to justify sinners. They pointed to the need for a greater salvation—a once-for-all sacrifice that could actually cleanse us from sin.
As Justin writes, God gave sacrifices and rituals “not because He needed them, but because of your sins.” They were temporary signs of a greater spiritual reality.
3. Christ Fulfills the Law—So We Don’t Return to the Shadows
When someone objects, “Why don’t you follow all the Old Testament laws?” the answer is not that Christians are being inconsistent. It’s that Christians understand something crucial: those laws have been fulfilled in Christ.
Jesus is our once-for-all sacrifice. Therefore, we no longer need animal offerings (Hebrews 10:12). Jesus is our righteousness. Therefore, we don’t attempt to justify ourselves through religious rituals. Jesus is our eternal rest. Therefore, we are not bound to the festival observance in the same way Israel was (Colossians 2:16–17).
This is why Christians don’t obey ceremonial and civil laws from the Old Testament. It’s not inconsistency—it’s covenant fulfillment.
Paul makes this point clearly in Galatians 3 and 4. The law was like a guardian or tutor until Christ came. Now that Christ has come, we are sons of God through faith and are no longer under the tutor.
So, How Should Christians Respond Today?
We can respond in the same way Justin Martyr did nearly 2,000 years ago:
- Clarify the kinds of law in the Old Testament. The moral law endures because it reflects God’s character and is written on the human heart. The ceremonial laws have been fulfilled in Christ and are no longer binding under the new covenant. And the civil laws expired with the nation of Israel when it was sent into exile.
- Affirm that righteousness comes by faith, not by law-keeping. Old Testament rituals pointed to the need for salvation, not the means to earn it. And now that Christ has come, we rest in his finished work.
- Celebrate the new covenant. We don’t follow the shadows because we have the substance—Jesus himself. His life, death, and resurrection have accomplished what the law could only foreshadow.
So no, Christians aren’t “just picking and choosing.” We’re following the one who fulfilled the law on our behalf—and calls us now to live by faith in him.
