An Analytical Study of Qalb, Ṣadr, Fu’ād, and Lubb in the Qur’an: Meaning, Hierarchy, and Interrelationship

Abstract

This article presents an analytical study of the Qur’anic concepts of qalb (heart), ṣadr (chest), fu’ād (inner heart), and lubb (pure intellect), examining their meanings, hierarchical order, and interrelationship within the Qur’anic worldview. Drawing on a close reading of Qur’anic verses, classical Arabic lexicons, and major works of Qur’anic exegesis, the study demonstrates that these terms do not function as mere synonyms, nor do they refer simply to a physical organ. Rather, they represent distinct yet interconnected dimensions of human inner consciousness, cognition, and moral responsibility. The article argues that ṣadr denotes the broad and initial inner domain where inclinations, desires, doubts, and openness or constriction toward guidance emerge; qalb functions as the central locus of faith, intention, understanding, and moral choice; fu’ād signifies the subtler faculty of intense perception, inner vision, and affective awareness; and lubb represents purified intellect and reflective consciousness, most clearly embodied in the Qur’anic category of ulū al-albāb. By situating these concepts in a coherent hierarchy, the study highlights the Qur’an’s integrated view of knowledge, faith, and action, showing that true guidance is not confined to rational cognition alone but is rooted in a harmonized inner structure combining perception, intention, ethical refinement, and spiritual illumination. The findings contribute to a deeper understanding of Qur’anic anthropology and the moral–epistemic foundations of human accountability in the Qur’an.