Exodus 20:21-26 NKJV
So the people stood afar off, but Moses drew near the thick darkness where God was.
Then 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. You shall not make anything to be with Me—gods of silver or gods of gold you shall not make for yourselves. An 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. And 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. Nor shall you go up by steps to My altar, that your nakedness may not be exposed on it.’
NKJV: New King James Version