Recalling the first verse, this final verse of the preamble introduces Moses' address. He will teach, expound, make absolutely clear the law, the very basis of the covenant between the Lord and Israel. Deuteronomy is thus in many ways a preaching—an exposition and application—of the law of the covenant of Sinai/Horeb. For God's people needed a word from God before entering the Promised Land.
5 Beyond the Jordan, in the land of Moab, Moses undertook to explain this law, saying,