Deuteronomy 31:26

Take this book — Probably the very same book, which (after having been some way misplaced) was found in the house of the Lord, in the days of Josiah, and publickly read by the king himself, for a witness against a people, who were then almost ripe for ruin. In the side — In the outside, in a little chest fixed to it, for nothing but the tables of stone were contained in the ark, 1 Kings 8:9, here it was kept for greater security and reverence. A witness against thee — Against thy people, to whom he turns his speech that they might be the more affected with it.