The study of the theology and ethics of the Old Testament is a well-traversed path in scholarship. For this area of study, scholars have attempted to provide equal weight to the entirety of the canon in order to better understand its theological and ethical vision as a whole rather than only focus upon one book or genre. However, one area has been given considerably less attention: the genealogical material of the Old Testament. When such material is examined, it is largely through a diachronic rather than synchronic lens. Unfortunately, while such studies are valuable, the theology and ethics of genealogies have been given insufficient attention. As such, this paper seeks to contribute to the broader task of Old Testament theology and ethics through an examination of the Davidic genealogy in Ruth 4:18–22 and 1 Chr 2:9–15. Previous studies of this synoptic genealogy have largely focused upon historiographical and source-critical concerns, such as in the work of Roddy Braun, Sara Japhet, Edward Campbell, and Ralph Klein (to name but a few). While the Davidic genealogy comprises a considerably short segment of the genealogy of 1 Chr 1–9 (and the only genealogy within the book of Ruth), attention to it can help to reveal how genealogies function theologically and ethically concerning issues of identity and foreignness—a key concern of the book of Ruth and Chronicles in general. Therefore, this paper first provides an overview of many of the macro features of genealogies—definition, form, and function—and then turns to the more specific aspects of the extended genealogy of 1 Chr 1–9. I then focus upon the key elements of the Davidic genealogy between Ruth 4:18–22 and 1 Chr 2:9–15. Finally, drawing from the material in the previous sections, this paper provides several observations concerning the importance of the Davidic genealogy to Old Testament theology and ethics, particularly regarding foreignness and the identity of the people of God. Ultimately, when considered in tandem and in the broader context of Ruth and 1 Chr 1–9, the Davidic genealogy presents a complex theological and ethical statement on foreignness and identity, with the people of God being entirely under Davidic rule and worshipping YHWH alone.