Arthur Peake's Commentary on the Bible
Deuteronomy 9 - Introduction
Deuteronomy 5-11. Moses'second Address. This contains laws (Deuteronomy 5:6) and (mainly) exhortation based on the fundamental conception of Yahweh's uniqueness. This discourse had probably an independent origin, but it is exceedingly homogeneous, and conforms throughout with the type of composition characteristic of D. Many of the best scholars, including Driver, regard Deuteronomy 5-26 with Deuteronomy 28 as one continuous composition, not improbably (they think) the original D code.
Deuteronomy 6-11. Consists of a lengthy homily based on the first commandment (Deuteronomy 5:6). Israel is to worship and serve Yahweh alone.