The LORD said to Moses, "You and Aaron, Nadab and Abihu, and 70 of the elders of Israel must come up to me. Do not come close when you worship.
References for Exodus 24:1
Only Moses can come close to me. The others must not come near. And the people may not go up with him."
Moses went and told the people all of the LORD's words and laws. They answered with one voice. They said, "We will do everything the LORD has told us to do."
Then Moses wrote down everything the LORD had said. Moses got up early the next morning. He built an altar at the foot of the mountain. He set up 12 stone pillars. They stood for the 12 tribes of Israel.
Then he sent young Israelite men to offer burnt offerings. They also sacrificed young bulls as friendship offerings to the Lord.
Moses took half of the blood and put it in bowls. He sprinkled the other half on the altar.