Should Ancient Religious Laws Apply Today? Judaism, Christianity & Islam Compared

For Judaism, the question isn't really whether ancient religious laws apply — it's how they apply. The Torah's commandments (mitzvot) are understood as an eternal covenant between God and the Jewish people. The Talmud, Mishnah, and centuries of rabbinic commentary exist precisely to keep those ancient laws alive and operative in changing circumstances.

2 Kings 17:34 offers a pointed warning against abandoning ancestral practice: the text criticizes those who do not follow the laws and practices God enjoined upon the descendants of Jacob 2 Kings 17:34. This framing treats ongoing observance as a baseline expectation, not an optional heritage.

The Mishnah itself — compiled around 200 CE by Rabbi Judah ha-Nasi — demonstrates this dynamic in action. Even highly technical rulings, like the detailed purity laws of Mishnah Keilim, were actively debated and applied long after the Temple's destruction Mishnah Keilim 17:14. Rabbi Yohanan ben Nuri's challenge within that very passage shows that ancient law wasn't frozen; it was argued over, refined, and kept living.

Genesis 47:26 is an interesting counterpoint: it records a law Joseph instituted in Egypt that became a 'land law still valid' in its day Genesis 47:26. Rabbinic readers have long noted that even human-instituted laws can persist across generations — how much more so divine ones.

Modern Jewish denominations do disagree on scope. Orthodox Judaism holds that halakha is fully binding. Conservative Judaism accepts the law's authority but allows historical-critical methods to guide reinterpretation. Reform Judaism treats the ethical core as binding while regarding ritual law as a matter of individual choice. But across all these streams, ancient law is taken seriously as a starting point, not dismissed.

Christianity's relationship to ancient religious law is genuinely complicated, and honest scholarship has to acknowledge that. Paul's letters in particular pull in what can feel like opposite directions. On one hand, Romans 3:31 insists that faith doesn't nullify the law: 'Do we then make void the law through faith? God forbid: yea, we establish the law.' Romans 3:31 On the other hand, Paul elsewhere describes sin as having reigned before the law and as not being 'imputed when there is no law' Romans 5:13, suggesting the law's role is historically situated.

Romans 7:21 adds another layer: 'I find then a law, that, when I would do good, evil is present with me' Romans 7:21 — here 'law' seems to describe a moral reality built into human experience, not just a Mosaic statute. This has led theologians from Augustine to Martin Luther (16th century) to distinguish between the law's convicting function and its ceremonial or civil functions.

The classic Protestant framework, developed by Calvin and others, divides Mosaic law into three categories: moral (still binding, summarized in the Ten Commandments), ceremonial (fulfilled in Christ and no longer obligatory), and civil (specific to ancient Israel, not directly applicable today). Catholic and Orthodox traditions have their own nuanced positions, generally affirming natural law as the foundation while treating Mosaic specifics as fulfilled rather than abolished.

There's real disagreement here. Theonomists like Rousas Rushdoony (20th century) argued that biblical law should govern civil society. Mainstream evangelical and mainline Protestant scholars push back strongly, arguing that the New Covenant recontextualizes the law's application. The debate is live, not settled.

Islam's position is that divine law has always been the foundation of right living, and that the Qur'an represents its final, authoritative form. Crucially, the Qur'an doesn't simply replace earlier scriptures — it calls the People of the Scripture to uphold their own revealed laws. Quran 5:66 states that if the Jews and Christians had upheld the Torah, the Gospel, and what was revealed to them from their Lord, they would have received divine blessing Quran 5:66. Quran 5:68 sharpens this: 'you are standing on nothing until you uphold the law of the Torah, the Gospel, and what has been revealed to you from your Lord' Quran 5:68.

This framing is significant. Islam doesn't treat ancient religious law as obsolete — it treats the failure to uphold it as a spiritual catastrophe. The Qur'an's critique of earlier communities is precisely that they abandoned or distorted their own divinely given law.

For Muslims themselves, the operative ancient law is Sharia — derived from the Qur'an and Sunnah (the Prophet Muhammad's practice, d. 632 CE). Classical scholars like al-Shafi'i (d. 820 CE) developed sophisticated legal methodology (usul al-fiqh) to apply these sources to new situations. Contemporary Muslim scholars debate how much of classical fiqh (jurisprudence) remains directly applicable in modern nation-states, but the principle that divine law should govern human life isn't seriously contested within the tradition.

There's genuine internal disagreement between traditionalist, reformist, and modernist Muslim thinkers about application — but not about the authority of ancient divine law in principle.

From a Jewish textual lens, divine law (Torah and its commandments) remains binding upon Israel, and failure to follow it is censured as departing from proper worship 2 Kings 17:34. Rabbinic tradition operationalizes this endurance of law by applying detailed regulations—e.g., purity categories in the Mishnah—signaling that ancient commandments are meant to be interpreted and lived in concrete, ongoing ways Mishnah Keilim 17:14. Even the Hebrew Bible notes the persistence of specific enacted laws over time (as with a land law remaining “still valid”), which illustrates a scriptural precedent for legal continuity across generations Genesis 47:26.

Paul rejects the idea that faith nullifies God’s law; instead, he says faith establishes the law, showing that the law hasn’t been simply discarded Romans 3:31. Yet Paul also parses the law’s function: before the law, sin wasn’t held to account in the same way, and recognizing this dynamic shows why Christians have wrestled with how the law applies post-Christ Romans 5:13. On a personal-moral level, Paul describes the struggle to do good while confronting evil’s presence, underscoring the law’s searching role in the believer’s life and the need for divine grace Romans 7:21.

The Qur’an commands the People of the Scripture to uphold the Torah, the Gospel, and what has been revealed from God, presenting such upholding as the only valid standing, which affirms the ongoing relevance of God’s revealed laws as guidance Quran 5:68. It also promises bounty for those who uphold these revelations, while acknowledging that among the People of the Scripture are both moderate adherents and many who do wrong Quran 5:66.