Albert Barnes Commentary Deuteronomy 31:11

"when all Israel is come to appear before Jehovah thy God in the place which he shall choose, thou shalt read this law before all Israel in their hearing." — Deuteronomy 31:11 (ASV)

Compare the marginal references.

It should not be supposed that the whole of the Pentateuch was read, nor does the letter of the command require that it should be so. This reading could not be primarily designed for the information and instruction of the people, since it only took place once in seven years; but was evidently a symbolic transaction, intended, like so many others, to impress upon the people the conditions on which they held possession of their privileges and blessings.