Deuteronomy 31:9

This law, largely so called, the whole law or doctrine delivered unto Moses contained in these five books. Delivered it unto 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. Which bare the ark, to wit, sometimes in great solemnities, as Joshua 3:13,17 Joshua 6:12 1 Kings 8:3; though the Levites also might bear it, as appears from Num 3 Num 4 Num 10 1 Chronicles 15:2. The elders of Israel were assistants to the priests, and overseers to take care that the law should be kept, and read, and observed.