17:11-14 How does blood make atonement for sin? when offered with the right attitude, the sacrifice and the blood shed from it made forgiveness of sin possible. On the one hand, blood represented the sinner's life, infected by his sin and headed for death. On the other hand, the blood represented the innocent life of the animal that was sacrificed in place of the guilty person making the offering. The death of the animal (of which the blood was proof) fulfilled the penalty of death. God therefore granted forgiveness to the sinner. It is God who forgives based on the faith of the person doing the sacrificing.
17:14 Why was eating or drinking blood prohibited? The prohibition against eating blood can be traced all the way back to Noah (Genesis 9:4). God prohibited eating or drinking blood for several reasons. (1) To discourage pagan practices. Israel was to be separate and distinct from the foreign nations around them. Eating blood was a common pagan practice. It was often done in hopes of gaining the characteristics of the slain animal (strength, speed, etc.). God's people were to rely on him, not on ingested blood, for their strength. (2) To preserve the symbolism of the sacrifice. Blood symbolized the life of the animal that was sacrificed in the sinner's place. To drink it would change the symbolism of the sacrificial penalty and destroy the evidence of the sacrifice. (3) To protect the people from infection because many deadly diseases are transmitted through the blood. The Jews took this prohibition seriously, and that is why Jesus' hearers were so upset when Jesus told them to drink his blood (John 6:53-56). However, Jesus, as God himself and the last sacrifice ever needed for sins, was asking believers to identify with him completely. He wants us to take his life into us, and he wants to participate in our lives as well.