Exodus 20:22-26 - Instructions For Building Altars
22 And Jehovah said to Moses, So you shall say to the sons of Israel, You have seen that I have talked with you from the heavens. 23 You shall not make with Me gods of silver, neither shall you make to you gods of gold.
24 You shall make an altar of earth to Me, and shall sacrifice on it your burnt offerings and your peace offerings, your sheep and your oxen. In all places where I record My name I will come to you, and I will bless you. 25 And if you will make Me an altar of stone, you shall not build it of cut stone. For if you lift up your tool upon it, you have defiled it. 26 And you shall not go up by steps to My altar, that your nakedness be not uncovered on it.