Deuteronomy 31:26 in the King James Version
Take this book of the law, and put it in the side of the ark of the covenant of the LORD your God, that it may be there for a witness against thee.
Context
25 Moses commanded the Levites, who bore the ark of the LORD’s covenant, saying,
26 “Take this book of the law, and put it by the side of the ark of the LORD your God’s covenant, that it may be there for a witness against you.
27 For I know your rebellion and your stiff neck. Behold, while I am yet alive with you today, you have been rebellious against the LORD. How much more after my death?