Exodus 20:18-24 New Revised Standard Version (NRSV)
18 When all the people witnessed the thunder and lightning, the sound of the trumpet, and the mountain smoking, they were afraid[a] and trembled and stood at a distance, 19 and said to Moses, “You speak to us, and we will listen; but do not let God speak to us, or we will die.” 20 Moses said to the people, “Do not be afraid; for God has come only to test you and to put the fear of him upon you so that you do not sin.” 21 Then the people stood at a distance, while Moses drew near to the thick darkness where God was.
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.