It is my impression that some interpreters have distinguished between the two sections on the grounds that chapters 40–55 sound more “Christian,” stressing God’s universalism and the redemptive power of suffering, while chapters 56–66 sound more “Jewish,” focused on ritual and vengeance. This is a notorious false dichotomy with deep roots in the field. But since other arguments against the unity of chapters 40–66 retain their force, the matter is best left open.