Customary Law System and the Influence of Religion on the Indonesian Legal System

Abstract

This paper comprehensively examines the system of customary law (hukum adat) in Indonesia and the influence of religion on the formation, development, and implementation of the national legal system. Customary law, as the indigenous legal system of the Indonesian people, has existed long before the arrival of colonial influences and major world religions such as Hinduism, Buddhism, and Islam. Historically, hukum adat not only served as a social guideline but also as a reflection of the nation’s moral, spiritual, and cultural values. Its evolution has undergone significant transformations—from the Hindu–Buddhist kingdoms that marked the early integration of religious and customary norms, to the Islamic kingdoms that produced a syncretic blend of syariah and customary law, and finally, to the Dutch colonial period which institutionalized legal pluralism through the Western legal system. Following Indonesia’s independence, a major challenge arose in unifying the various legal systems into a coherent national legal framework grounded in the values of Pancasila and the 1945 Constitution. Religion, as a source of ethical and moral principles, has exerted a profound influence on the substance and philosophy of Indonesian law. Islamic law, for instance, has significantly shaped family law, civil law, and Islamic economic law, while other religions have also contributed to the moral and philosophical dimensions of national law. In the modern era, globalization and legal modernization pose new challenges to maintaining the relevance of both customary and religious law amidst demands for universal justice and efficiency. This study aims to analyze the historical roots, interrelations, and harmonization potential between customary law, religious law, and the national legal system. Using a historical-philosophical and normative approach, it seeks to formulate an ideal concept for developing a national legal system that remains rooted in Indonesia’s  cultural identity. The findings indicate that the integration of customary and religious law into the national legal framework is not merely a juridical process but also a cultural and philosophical one. Therefore, the construction of national law must always be grounded in spirituality, local wisdom, and social justice as embodied in Pancasila as the ultimate source of all Indonesian law