‌Context & Objective: Hugo Grotius, widely recognized as the father of modern international law, articulated a distinct theory of natural law in his seminal work, De Jure Belli ac Pacis (On the Law of War and Peace), declaring that natural laws possess an immutable rational necessity that even the divine will cannot alter. This conceptualization, departing from Thomas Aquinas's integration of natural law within the eternal divine law, has historically prompted various legal scholars to characterize Grotian jurisprudence as a pivotal step toward the secularization of natural law. The discussion in this study outlines the epistemological, ontological, and theological foundations of Grotius’s theory, examining how this rational autonomy impacts the structural relationship between reason and revelation. Consequently, the primary research purpose of this study is to challenge the prevailing secular paradigm surrounding Grotian jurisprudence. The central research question is whether Grotius's interpretation of natural law inevitably leads to a secularized legal framework, or whether a jurisprudential reading can be constructed that maintains the rational immutability of natural law while preserving its intrinsic, harmonious relationship with the divine will and the system of Sharia.
 ‌Method & Approach: To address this question, this study adopts a doctrinal methodology combined with a comparative, analytical-deductive approach. Due to the relative scarcity of direct philosophical-theological treatises written by Grotius on the precise relationship between reason and divine command, this research utilizes an inferential analysis of his foundational legal writings, particularly the Prolegomena to De Jure Belli ac Pacis. This Grotian framework is then comparatively evaluated alongside the scholastic theology (Kalam) of the Shia (Imami) intellectual tradition. Utilizing a logical-deductive model, the study bridges the conceptual gap between classical Shia theology and modern natural law theories. Specifically, by examining the Shia theological doctrine of rational goodness and badness (al-ḥusn wa-l-qubḥ al-ʿaqliyyān), the study establishes a robust comparative framework to evaluate how autonomous rational norms can coexist with, and be validated by, divine legislation.
 ‌Findings: The findings of this study demonstrate that Grotius's conceptualization of natural law is structurally analogous to the theological and jurisprudential doctrines of Shia (Imami) scholars concerning rational morality. Shia theologians posit that certain moral acts possess inherent, objective goodness or badness (ḥusn and qubḥ) that can be independently discovered by human reason. Crucially, the Shia school does not view this rational autonomy as a threat to divine sovereignty; rather, they argue that these rational dictates are simultaneously commanded by God, establishing a vertical or longitudinal relationship between divine Sharia and the sound perceptions of human reason. The study reveals that Grotius similarly categorizes laws into distinct domains: rational/natural laws commanded by God due to their inherent morality, divine voluntary (positive) laws dictated solely by divine will, and human voluntary laws. Therefore, the Grotian assertion of the immutability of natural law does not exclude the divine, but rather mirrors the Shia theological view that rational moral truths exist prior to, yet are perfectly aligned with, divine legislative will.
 ‌Conclusion: This study demonstrates that interpreting Grotius's natural law as an inherently secularized construct is a jurisprudential and historical inaccuracy. By leveraging the theological insights of the Shia intellectual tradition, the paper proves that a synthesis of autonomous reason and divine law is not only conceptually coherent but also structurally viable. The Grotian framework, much like Shia theology, maintains a complementary rather than adversarial relationship between reason and revelation. Ultimately, this comparative analysis offers a novel jurisprudential paradigm: a rational, yet deeply theological, reading of natural law that transcends the rigid secular-religious dichotomy, proving that the rationalization of law does not necessitate its secularization.