The theological significance of Deuteronomy can scarcely be overestimated. Inasmuch as this book offers the most systematic presentation of theological truth in the entire Old Testament, we may compare its place to that of Romans in the New Testament. Moreover, since Deuteronomy reviews so much of Israel’s historical experience of God’s grace as recounted in Genesis through Numbers, a comparison with the gospel of John may be even more appropriate. Just as John wrote his gospel after several decades of reflection on the death and resurrection of Jesus, so Moses preached the sermons in Deuteronomy after almost four decades of reflection on the significance of the Exodus and God’s covenant with Israel. Thus, like the gospel of John, the book of Deuteronomy functions as a theological manifesto, calling on Israel to respond to God’s grace with unreserved loyalty and love.
(NIVAC: Deuteronomy, 25)