Then Moses and the elders of Israel charged all the people as follows: Keep the entire commandment that I am commanding you today.
On the day that you cross over the Jordan into the land that the Lord your God is giving you, you shall set up large stones and cover them with plaster.
You shall write on them all the words of this law when you have crossed over, to enter the land that the Lord your God is giving you, a land flowing with milk and honey, as the Lord, the God of your ancestors, promised you.
So when you have crossed over the Jordan, you shall set up these stones, about which I am commanding you today, on Mount Ebal, and you shall cover them with plaster.
And you shall build an altar there to the Lord your God, an altar of stones on which you have not used an iron tool.
You must build the altar of the Lord your God of unhewn stones. Then offer up burnt offerings on it to the Lord your God,
References for Deuteronomy 27:6