Deuteronomy 31:24-26

Thomson(i) 24 Now when Moses had made an end of writing all the words of this law in a book, even to the close, 25 he gave a charge to the Levites, who carry the ark of the covenant of the Lord, saying, 26 Take this book of the law; and put it by the side of the ark of the covenant of the Lord your God; and it shall be there for a witness against thee;