Exodus 20:22-26

22Then the Lord said to Moses, “Thus you shall say to the children of Israel: ‘You have seen that I have talked with you from heaven.

23You shall not make anything to be with Me—gods of silver or gods of gold you shall not make for yourselves.

24An altar of earth you shall make for Me, and you shall sacrifice on it your burnt offerings and your peace offerings, your sheep and your oxen. In every place where I record My name I will come to you, and I will bless you.

25And if you make Me an altar of stone, you shall not build it of hewn stone; for if you use your tool on it, you have profaned it.

26Nor shall you go up by steps to My altar, that your nakedness may not be exposed on it.’