Deuteronomy 27:5-7

5And there shalt thou build an altar to Jehovah thy 1God, an altar of stones; thou shalt not lift up an iron [tool] upon them;

6of whole stones shalt thou build the altar of Jehovah thy 2God; and thou shalt offer up burnt-offerings thereon to Jehovah thy 3God.

7And thou shalt sacrifice peace-offerings, and shalt eat there, and rejoice before Jehovah thy 4God.