Exodus 24:4-7

Moses wrote down all the words of the LORD. Then he arose early in the morning, and built an altar at the foot of the mountain with twelve pillars for the twelve tribes of Israel. He sent young men of the sons of Israel, and they offered burnt offerings and sacrificed young bulls as peace offerings to the LORD. Moses took half of the blood and put it in basins, and the other half of the blood he sprinkled on the altar. Then he took the book of the covenant and read it in the hearing of the people; and they said, “All that the LORD has spoken we will do, and we will be obedient!”