And Moses wrote this law, and delivered it unto the priests the sons of Levi, which bare the ark of the covenant of the LORD, and unto all the elders of Israel.

Wesley's Notes

31:9 This law - Largely so called, the whole law or doctrine delivered unto Moses contained in these five books. To the priests - That they might keep it carefully and religiously, and bring it forth upon occasion, and read it, and instruct the people out of it. The elders - Who were assistants to the priests, to take care that the law should be kept, and read, and observed.

Jamieson-Fausset-Brown Bible Commentary

De 31:9-13. He Delivers the Law to the Priests, to Read It Every Seventh Year to the People.

9-13. And Moses wrote this law, and delivered it unto the priests-The law thus committed to writing was either the whole book of Deuteronomy, or the important part of it contained between the twenty-seventh and thirtieth chapters. It was usual in cases of public or private contract for two copies of the engagement to be made-one to be deposited in the national archives or some secure place for reference, should occasion require. The other was to remain in the hands of the contracting parties (Jer 32:12-14). The same course was followed on this renewal of the covenant between God and Israel. Two written copies of the law were prepared, the one of which was delivered to the public representatives of Israel; namely, the priests and the elders.

the priests, . who bare the ark of the covenant-In all ordinary journeys, it was the common duty of the Levites to carry the ark and its furniture (Nu 4:15); but, on solemn or extraordinary occasions, that office was discharged by the priests (Jos 3:3-8; 6:6; 1Ch 15:11, 12).

all the elders of Israel-They were assistants to the priests and overseers to take care of the preservation, rehearsal, and observance of the law.

Matthew Henry's Concise Commentary

31:9-13 Though we read the word in private, we must not think it needless to hear it read in public. This solemn reading of the law must be done in the year of release. The year of release was typical of gospel grace, which is called the acceptable year of the Lord; for our pardon and liberty by Christ, engage us to keep his commandments. It must be read to all Israel, men, women, children, and to the strangers. It is the will of God that all people should acquaint themselves with his word. It is a rule to all, therefore should be read to all. Whoever has read of the pains taken by many persons to get scraps of the Scriptures, when a whole copy could not be obtained, or safely possessed, will see how thankful we should be for the thousands of copies amongst us. They will also understand the very different situation in which the Israelites were placed for many ages. But the heart of man is so careless, that all will be found too little, to keep up a knowledge of the truths, precepts, and worship of God.