The Bible teaches that there must be a blood sacrifice for our sins. In the Old Testament we see this in the sacrificing of animals, all to point to one great sacrifice coming one day. In the New Testament the person of Jesus becomes the final sacrifice, so people are atoned for and free from maintaining their own standing with God. The standing is now secure, forgiven and righteous, by the work of Jesus.
So it raises two questions, isn’t all that quite barbaric, and second, why blood? Why does blood have to be shed?
#1: Isn’t all this quite barbaric?
Well, we view things different than God. We try to hold on to every living thing, but everything dies. It’s the cycle of life. God doesn’t seem to attempt to hold on to every living thing for another day like we do. He seems completely ok with killing things and letting them die. I wonder if our view of this would change if we had a greater sense that death is not finality. If death is a doorway then the killing of some animal is no different than leading them from one pasture to the next.
#2: Why does blood have to be shed?
Sin deserves justice, it always has and always will, and a loving being always has wrath towards sin, by nature and definition. God righteously does this – the good in him does this – his character being fully just demands action. Meaning, if you walked out of Wal-Mart and saw a five-year-old little girl being beaten by a grown man there would be no question that you have to stop it. You would be demanded to stop it by the good in you. Good always demolishes evil. Perhaps we think this is overboard, but we forget that sin is horrible. It’s not pleasure without effects. It eventually causes depression and hurt. It creates wounds that ache and rot people from the inside out.
Death is the penalty of sin; it’s the reality of sin. Sin leads to death; therefore blood is the means to escape the result/end of the disease within us. Atonement is about restoration, making things right again. The work of Jesus, the atonement he gives, is a gift to those who yield their wills and receive.
Here’s many more thoughts on the topic of atonement over at Monergism: