Deuteronomy 27:2-8

2And on the day you cross the Jordan into the land that the LORD your God is giving you, set up large stones and coat them with plaster. 3Write 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, just as the LORD, the God of your fathers, has promised you. 4And when you have crossed the Jordan, you are to set up these stones on Mount Ebal, as I am commanding you today, and you are to coat them with plaster.

5Moreover, you are to build there an altar to the LORD your God, an altar of stones. You must not use any iron tool on them. 6You shall build the altar of the LORD your God with uncut stones and offer upon it burnt offerings to the LORD your God. 7There you are to sacrifice your peace offerings, eating them and rejoicing in the presence of the LORD your God. 8And you shall write distinctly upon these stones all the words of this law.”