The doctrine of the religious authority (al-marjaʿiyyah al-dīniyyah) of the Ahl al-Bayt (a) has emerged in recent years as a novel framework for re-evaluating the station of the Imamate; however, it has occasionally faced the accusation of being a modern construct lacking roots in the Shi‘i tradition. With the aim of investigating the historical background and the hadith-based foundations of this concept, this research first defines "religious authority" and subsequently provides a structural and content analysis of the Kitāb al-Hujjah (Book of the Proof) within the compendium of al-Kāfī. This study endeavors to unveil the relationship between the concept of the "religious authority" and the title of "Proof" (Hujjah) in the narrational heritage of the Imamiyyah. This qualitative research utilizes a descriptive-analytical approach through content analysis, with data gathered and analyzed via library sources. The findings indicate that al-Kulayni, through the purposeful categorization (tabwīb) of the chapters in Kitāb al-Hujjah and the selection of pivotal narrations, has delineated an epistemological constellation to explicate the station of the Imams (a) in human guidance. The focus on the title "Proof" within this organizational structure signifies al-Kulayni’s understanding of the Imam as the religious authority of the community—an understanding that overlaps with the contemporary conceptual framework of religious authority. The present research demonstrates that religious authority is not a late concept but rather a deeply rooted structure within the Shi‘i narrational tradition that was present in the hadith-oriented mindset of al-Kulayni.