Exodus 24:4-6

New Catholic Bible

⁴ Moses wrote down all the words of the Lord. Then he rose early in the morning and built an altar at the foot of the mountain with twelve pillars for the twelve tribes of Israel. ⁵ He sent some of the young men of Israel to offer burnt offerings and to sacrifice young bulls as peace offerings to the Lord.

⁶ Moses took half of the blood and placed it in bowls and the other half of the blood he poured out on the altar.