This essay argues that biblical genealogy serves as a fundamental organizing principle in the Qurʾān. In particular, the Qurʾān anchors the cultic and scriptural aspects of the Prophet’s mission squarely on his community’s descent from Abraham via Ishmael. The first part of the essay marshals qurʾānic evidence in support of this claim and critiques a number of recent studies that downplay or deny the significance of Abrahamic-Ishmaelite genealogy in the Qurʾān. The second part reinforces this significance by demonstrating that Ishmael’s qurʾānic characterization as an upright prophet sharply contrasts with his predominantly negative portrayals in pre-Islamic writings. The final part shows that modern scholars initially acknowledged Abraham and Ishmael’s key ancestral and cultic roles in the Qurʾān but came to see these roles as exclusively Medinan constructs. The essay challenge this view and offers a different explanation for the Qurʾān’s varying portrayals of Abraham and Ishmael.