Deuteronomy 27:1-5

Then Moses and the elders of Israel commanded the people, saying, “Keep all the commandments which I am commanding you today.

So it shall be on the day when you cross the Jordan to the land which the Lord your God is giving you, that you shall set up for yourself large stones and coat them with lime

and write on them all the words of this Law, when you cross over, so that you may enter the land which the Lord your God is giving you, a land flowing with milk and honey, just as the Lord, the God of your fathers, promised you.

So it shall be when you cross the Jordan, you shall set up these stones on Mount Ebal, as I am commanding you today, and you shall coat them with lime.

Moreover, you shall build there an altar to the Lord your God, an altar of stones; you shall not wield an iron tool on them.