Exodus 24:1-6

He said to Moses, “Climb the mountain to GOD, you and Aaron, Nadab, Abihu, and seventy of the elders of Israel. They will worship from a distance; only Moses will approach GOD. The rest are not to come close. And the people are not to climb the mountain at all.” So Moses went to the people and told them everything GOD had said—all the rules and regulations. They all answered in unison: “Everything GOD said, we’ll do.” Then Moses wrote it all down, everything GOD had said. He got up early the next morning and built an Altar at the foot of the mountain using twelve pillar-stones for the twelve tribes of Israel. Then he directed young Israelite men to offer Whole-Burnt-Offerings and sacrifice Peace-Offerings of bulls. Moses took half the blood and put it in bowls; the other half he threw against the Altar.