This paper investigates how encounters between Qurʾanic and Biblical texts were addressed within the discipline of tafsīr, taking the works of al-Biqāʿī as a case study. Rather than approaching these encounters as instances of interreligious dialogue in a modern sense, the study examines the internal mechanisms through which Abrahamic textual dynamics operated within Qurʾanic exegesis itself. The analysis focuses on al-Biqāʿī's Naẓm al-durar, a pioneering commentary that places semantic and structural coherence (tanāsub, munāsabāt) at the center of Qurʾanic interpretation. It explores how Biblical material is mobilized within this exegetical framework and how such material is differentiated from, yet positioned in relation to, isrāʾīliyyāt traditions. In order to clarify the epistemic and methodological conditions governing this practice, the paper also examines al-Biqāʿī's treatise al-Aqwāl al-qawīma, which addresses the permissibility of citing the Bible in Qurʾanic exegesis. Particular attention is given to the criteria regulating transmission, the classification of sources, and the differentiated treatment of Biblical corpora, including the New Testament. By analyzing these two works in conjunction, the paper highlights how Abrahamic textual interdependence functioned as an internally regulated exegetical practice embedded in the ʿulūm al-Qurʾān. The study thus contributes to a more precise understanding of how Qurʾanic exegesis managed scriptural proximity, distinction, and authority in the late medieval period. - ABRAHAMIC DYNAMICS -