Exodus 20:22-24 New Revised Standard Version (NRSV)
The Law concerning the Altar
22 The Lord said to Moses: Thus you shall say to the Israelites: “You have seen for yourselves that I spoke with you from heaven. 23 You shall not make gods of silver alongside me, nor shall you make for yourselves gods of gold. 24 You need make for me only an altar of earth and sacrifice on it your burnt offerings and your offerings of well-being, your sheep and your oxen; in every place where I cause my name to be remembered I will come to you and bless you.