Imam Ali (peace be upon him) in Nahj al-Balagha has been examined. The central issue is to investigate the extent of convergence and divergence between these two intellectual systems regarding foundational concepts in the field of ethics such as “good will,” “the absolute command,” “duty,” “intention,” “reason,” and “the place of religion.” The research method is descriptive-analytical with a comparative approach, and the data were extracted through a library study of Kant’s primary texts (such as Groundwork of the Metaphysics of Morals and Religion within the Limits of Pure Reason) and Nahj al-Balagha, and then subjected to comparative analysis. The findings show that despite apparent similarities in emphasizing the importance of intention, duty, and the intrinsic value of the human being, there are fundamental differences between the two views. The main cause of these differences lies in Kant’s anthropocentrism and the self-sufficiency of reason in his system versus the theocentrism and the revelatory nature of ethics in the intellectual framework of Nahj al-Balagha. This contrast in foundations leads to differences in the definition of the “absolute command” — reason-based versus divinely based — the source of duty (autonomous reason versus the sacred lawgiver), and also the role of “happiness” and “resurrection” in motivating and teleologically orienting moral action. The overall conclusion indicates that although Kantian ethics makes major contributions in the realm of rational deontology and in providing a universal criterion, the ethical system of Nahj al-Balagha, with its solid metaphysical backing, stronger motivation (a combination of reason, emotion, and faith), and a sublime teleology (nearness to God), possesses greater comprehensiveness, coherence, and practical efficacy in guiding individual and social life.