24:6-8 To understand this unusual covenant ratification ceremony, we need to understand the Bible's view of sin and forgiveness. God is the sovereign judge of the universe. He is also absolutely holy. As the holy judge of all, he condemns sin and judges it worthy of death. In the Old Testament God accepted the death of an animal as a substitute for the sinner. The animal's shed blood was proof that one life had been given for another. So on the one hand, blood symbolized the death of the animal, but it also symbolized the life that was spared as a result. Of course the death of the animal that brought forgiveness in the Old Testament was only a temporary provision, looking forward to the death of Jesus Christ (Hebrews 9:9-10:24).
In this ceremony described here, Moses sprinkled half the blood from the sacrificed animals on the altar to show that the sinner could once again approach God because something had died in his place. He sprinkled the other half of the blood on the people to show that the penalty for their sin had been paid and they could be reunited with God. Through this symbolic act God's promises to Israel were reaffirmed and lessons are taught to us about the future sacrificial death (or atonement) of Jesus Christ.