John Gill Commentary Deuteronomy 31:24

"And it came to pass, when Moses had made an end of writing the words of this law in a book, until they were finished," — Deuteronomy 31:24 (ASV)

And it came to pass, when Moses had made an end of writing
the words of this law in a book
In this book of Deuteronomy, and which concluded the Pentateuch:

until they were finished ;
all the words of the law, and the whole five books of Moses, excepting some few verses, (Deuteronomy 34:1–12) , which were added by another hand, Joshua or Ezra.