If we are cut, we all bleed. If we don't have enough blood, we will die. Blood is an essential physical component to the human body. It may seem like a strange topic to discuss on a pastor's blog, but the bible makes it one we should think through. Consider this mention of blood to Noah as he now lives in a new world after the flood. Genesis 9:4 But you shall not eat flesh with its life, that is, its blood. Noah was given all things (including animals) to eat, but the restriction was that he was not to consume blood. The blood of a creature is discussed in a way that it is almost synonymous with its life.
The prohibition of consuming blood is also found in the law for Israel in Leviticus 7 and 17. Leviticus 17:14 For the life of every creature is its blood: its blood is its life. Therefore I have said to the people of Israel, You shall not eat the blood of any creature, for the life of every creature is its blood. Whoever eats it shall be cut off. The reason blood is not to be consumed is because of its association with life. Even though humanity has been given everything including animals to eat, we are obviously meant to be respecters of life.
If that were all it is, one would say that might be enough, but there is a biblical reason that blood is so closely associated with life, and it is not just physical life. Before the law that prohibits consuming blood there is a law about the unnecessary spilling of animal blood. Leviticus 17:3-5 If any one of the house of Israel kills an ox or a lamb or a goat in the camp, or kills it outside the camp, 4 and does not bring it to the entrance of the tent of meeting to offer it as a gift to the LORD in front of the tabernacle of the LORD, bloodguilt shall be imputed to that man. He has shed blood, and that man shall be cut off from among his people. 5 This is to the end that the people of Israel may bring their sacrifices that they sacrifice in the open field, that they may bring them to the LORD, to the priest at the entrance of the tent of meeting, and sacrifice them as sacrifices of peace offerings to the LORD.
In the Old Covenant, the sacrificial system was a central and visible part of life. The people of Israel would constantly see the blood of animals flowing in sacrifice. It was to be a constant reminder of their need for salvation and their hope in the true atoning sacrifice that would cover their sin. They would fulfill their duties for sacrifice as given in the law, but the act was always to point them to something (Someone) greater. The sacrificial system was a constant reminder that the Seed of the woman would crush the serpent. It would happen through himself being crushed. In this way, the shedding of blood was not just an indication of the loss of life, but substitutionary atonement. It was sacred.
In Genesis 9, Noah was then instructed of the ultimate retribution for the shedding of human blood. Gen 9:5-6 And for your lifeblood I will require a reckoning: from every beast I will require it and from man. From his fellow man I will require a reckoning for the life of man. 6 "Whoever sheds the blood of man, by man shall his blood be shed, for God made man in his own image. Again, the physical blood is not the main point. We know that the life man is in our soul. After a human dies, our soul continues, and we stand before the Lord. So, why the emphasis on blood being shed?
I'll let John Calvin answer the question. Because we are so unlearned that we cannot reach the heights of understanding today what the life of souls is, our Lord, to accommodate our weakness, says that the blood is the life of man. In other words, when we shed human blood, it is the same as wanting to destroy the image of God and the life which he placed in us. Now that is sacrilege. It is no longer a simple act of violence between men, who are not the only ones injured, but that act is directed against God, as if we clearly despised him and had wanted to wage war against them. (1)
Everything points to the fact that God has created our lives to reflect Him. The shedding of the blood of an animal was to remind us that we need a substitute. The blood that we rely on for the sustenance of life should remind us that life is valuable and precious as image bearers of God.
Jesus, THE image of God, the exact imprint of His nature, laid down his life, shed his blood, so that we might live. I know we might sing songs like "There is Power in the Blood," but we are not saying something about a physical substance, we are talking about the power of the Son of God dying for our sins and rising from the dead so that we might have life.
The biblical discussion of blood really does become essential reading.
(1) John Calvin, Genesis Sermons.