Deuteronomy 31:9 - Joseph Benson’s Commentary on the Old and New Testaments

Moses wrote this law Largely so called, comprehending not only the contents of this book of Deuteronomy, but the whole law or doctrine delivered unto him, contained in these five books. Or rather it is probable the whole Pentateuch is here intended, which is the meaning of the word law in many parts of Scripture. And delivered it unto the priests Who were in duty bound to be peculiarly conversant with it, to keep it carefully and religiously, and to bring it forth upon occasion, and instruct the people out of it. And unto all the elders The magistrates, whose office it was to see that these laws of God were duly observed. The Jews allege that Moses, having delivered one copy unto the priests, gave one likewise to each tribe, which he committed to the care of the elders of it.