Why Do Religions and Nations Have Different, Even Conflicting, Laws?

Conclusion

Most traditions in these sources reckon directly with the fact that nations and communities live under different, even contradictory, laws, and most posit some law or right meant to hold beneath that plurality - a common core religion in Islam, a fixed moral law in Christianity, the Noahide minimum in Judaism, universal human rights in the secular declarations, and a single Hukam in Sikhism. They part sharply, however, on why the plurality exists and what governs it: Islam and Christianity treat it as willed or historically provisional under one God; Judaism and Hinduism tie it to a particular people, caste or cosmic age; Sikhism subsumes it under one metaphysical order; and the secular sources treat civil law as a human convention justified by utility, reserving universality only for rights. Buddhism's sources here do not address the question at all.

Where they agree

• Islam, Christianity, Judaism, Sikhism, and the secular declarations each posit some law or right meant to be common to all peoples beneath the visible plurality of national or communal law.
• Several traditions (Islam, Christianity, Judaism) treat the plurality of law among nations as an accepted, even divinely sanctioned, fact of history rather than something to be forcibly erased.
• None of the sources call for one nation's law to be imposed on all others by compulsion; several (Islam, secular) explicitly favor non-coercion in belief.

Where they differ

• Islam and Christianity ground legal plurality in one God's deliberate design (a test, or a stage before eschatological unity), while Judaism and Hinduism tie differing law to a particular people, caste, or cosmic age rather than to nations generally.
• Sikhism does not address competing national codes but resolves all diversity into a single divine Hukam, whereas the secular sources ground actual law in human convention and utility, reserving universality only for declared human rights.
• The single most important difference is the source of any universal law: revealed and divinely willed (Islam, Christianity, Judaism, Sikhism) versus humanly constructed and revisable, with rights alone claimed as universal (secular).