The Eusebian canon tables offered a detailed exegetical guide for formal gospel reading that is active and comparative. Though little evidence has been available for understanding how these tables were used by Greek writers, Matthew Crawford presents his discovery of a letter by Severus of Antioch who used Eusebius’ complicated system to help a colleague understand a Matthean variant of the piercing of Jesus’ side. Severus’ exegetical instructions are significant in demonstrating how gospel reading became a formal ecclesial practice aided by sophisticated tools and assumptions about the Fourfold Gospel in the Christian canon.