The concept of faith is at the core of Paul's theology, and the classic assage for his understanding of pistis is Genesis 15:6. After discussing the history of scholarship on the Pauline concept of faith, Benjamin Schliesser explores the literary, tradition-historical and structural questions of Genesis 15 and offers a detailed exegesis of verse 6 with its fundamental terms "count", "righteousness", and "believe". He then points to the theological significance of this testimony on Abraham for the Jewish identity; it comes into sight in a multifaceted and nuanced process of reception, from later Old Testament texts (Psalm 106; Nehemiah 9) to a broad array of literature from Second Temple Judaism (Septuagint, Sirach 44, Jubilees 14, 4QPseudo-Jubilees, 4QMMT, 1Maccabees, Philo). In the final and most substantial step, he asks about Paul's "hermeneutics of faith": How does Paul, in his exegesis of the Genesis quote in Romans 4, come to view Abraham as the father of all believers? What is the concept of faith that he develops on the basis of Genesis 15:6? Taking into account the manifold textual and thematic links between Romans 4, Romans 3:21-31, and Romans 1:16-17, a unique, twofold structure of "faith" discloses itself: Pistis designates first a divinely established sphere of power, i.e., a new, christologically determined salvation-historical reality, and second human participation in this reality, i.e., individual believing in the community of believers. Particularly the first aspect is generally overlooked in modern scholarship.