This paper examines the argument from case-precedent in the story of Jesus’ disciples plucking grain on the Sabbath (Mark 2:23–28 // Matt 12:1–8 and Luke 6:1–5), which appeals for a precedent to David and his men consuming the Bread of the Presence (1 Sam 21:1–6). Special attention is given to John Chrysostom’s perspicacious treatment of this story in one of his sermons on Matthew, particularly his analysis of the appeal to David through the concepts of pertinence (ti to pros to zētoumenon), equivalence (to ison), and exonerating principle (nomos apologias). A wider cultural context for understanding appeals to case-precedent is provided through brief surveys of such appeals in Roman law, oratory, and rabbinic interpretation (Mishnah).