Albert Barnes Commentary Deuteronomy 1:5

"Beyond the Jordan, in the land of Moab, began Moses to declare this law, saying," — Deuteronomy 1:5 (ASV)

In the land of Moab - This district had formerly been occupied by the Moabites, and retained its name from them; but it had been conquered by the Amorites. Compare Numbers 21:25 (see note); and Numbers 22:5 (see note).

Declare - That is, explain the Law already declared.