TWO SPECIFICATIONS IN LEVITICUS 17 constrained the ancient Israelite who wished to remain faithful to the covenant.
The first (17:1-9) limited sacrifices to what the Mosaic Covenant mandates and sanctions. Apparently some Israelites were offering sacrifices in the open fields, wherever they happened to be (17:5). Doubtless some of these were genuinely offered up to the Lord; others easily slid into syncretistic offerings devoted to local pagan deities (17:7). To bring sacrificial practice under the discipline of the tabernacle (and later the temple) was designed simultaneously to eliminate syncretism and to train up the people in the theological structures inherent in the Mosaic Covenant. Out there in the field it was all too easy to assume that these religious observances would win the favor of God (or the gods!), thereby securing good crops and nice kids. The tabernacle/temple system ideally brought the people under the tutelage of the Levites, teaching the people a better way. God himself had mandated this system. Only prescribed mediators and sacrifices were acceptable. The entire structure was designed to enhance the transcendence of God, to establish and clarify the sheer ugliness and vileness of sin, to demonstrate that a person could be accepted by God only if that sin were atoned for. Moreover, the system had two further advantages. It brought the people together for the thrice-annual festivals in Jerusalem, securing the cohesion of the covenant people; and it prepared the way for the supreme sacrifice in annual sacrifices that trained generations of believers that sin must be paid for in the way God himself prescribes, or there is no hope for any of us.
The second constraint imposed by this chapter (17:10-16) is the prohibition against eating blood. The reason given is specific: "For the life of a creature is in the blood, and I have given it to you to make atonement for yourselves on the altar; it is the blood that makes atonement for one's life" (17:11). The passage does not ascribe magical powers to blood. After all, the life is not in the blood apart from the rest of the body, and the strong prohibition against eating blood could never be perfectly carried out (since no matter how carefully you drain the blood from an animal there is always a little left). The point is that there is no life in the body where there is no blood; it is the obvious physical element for symbolizing the life itself. To teach the people how only the sacrifice of life could atone for sin — since the punishment of sin is death — it is difficult to imagine a more effective prohibition. We recall its significance every time we participate in the Lord's Table.
Leviticus 17; Psalms 20-21; Proverbs 31; 1 Timothy 2