Deuteronomy 27:4-7

So when you’ve crossed the Jordan, erect these stones on Mount Ebal. Then coat them with plaster. Build an Altar of stones for GOD, your God, there on the mountain. Don’t use an iron tool on the stones; build the Altar to GOD, your God, with uncut stones and offer your Whole-Burnt-Offerings on it to GOD, your God. When you sacrifice your Peace-Offerings you will also eat them there, rejoicing in the Presence of GOD, your God.