Scholars have long recognized the importance of Paul's citations from the Pentateuch for understanding the argument of Galatians. But what has not been fully appreciated is the key role that Isaiah plays in shaping what Paul says and how he says it, even though he cites Isaiah explicitly only once (Isaiah 54:1 in Galatians 4:27). Using an intertextual approach to trace more subtle appropriations of Scripture (i.e., allusions, echoes and thematic...