Leviticus 17:11-12

17:11 for the life of every living thing is in the blood. So I myself have assigned it to you on the altar to make atonement for your lives, for the blood makes atonement by means of the life. 17:12 Therefore, I have said to the Israelites: No person among you is to eat blood, and no resident foreigner who lives among you is to eat blood.