"Then [Moses] took the Book of the Covenant and read it to the people. They responded, “We will do everything the LORD has said; we will obey” (Exodus 24:7).
In Genesis 15, God told Abram in a dream to kill animals and separate them in halves. God walked between the pieces of the animals. We know that this meant God was saying, “May I be ripped in half if I fail to keep this covenant with Abram.”
The same kind of thing happens in Exodus 24. Moses set up an altar at the foot of Mount Sinai; the altar represented the presence of God. Across from the altar Moses set up twelve stone pillars representing Israel. He then had animals sacrificed, dividing the blood into two portions. Half he sprinkled on the altar and half he sprinkled on the people (probably by sprinkling it on the pillars that represented the two million people).
This action had a double meaning. On one hand, it represented a bond between God and Israel, a bond created by the sacrificed animal whose blood was put on both God and Israel. In the new covenant, the blood of Jesus the Mediator creates the bond between God and us.
On the other hand, this action also constituted an oath on the part of Israel to keep the law. Before Moses slew the animals, Israel pledged to keep all the law. Again, after Moses put the blood on the altar but before he put it on the people (or on their pillars), Moses read the Book of the Covenant and Israel pledged to obey it. Only then did Moses sprinkle the people with blood. The blood was on them and they were thereby bound in covenant with God, obliged to fulfill all they had just sworn to uphold.
The blood bound the people to God and to the law. If they as a nation broke the law, then their blood would be forfeit. They would no longer be bound to God and the blood of the sacrifice would no longer cover for their sins. Instead, they would bear their own guilt and would be chastised by God for their personal and national responsibility. The severity of the punishment (as later seen in the fall of the northern kingdom and also of Jerusalem and Judah), would seem to them as severe as if they had become like the severed animal sacrifices.
In new covenant worship, we hear the gospel proclaimed and we pledge to keep it, trusting in the blood of Christ that joins us to God. When we eat the Lord’s Supper, if we are not faithful, we stand under the same threat God pronounced against Israel. But if we trust in His blood we need never fear His wrath.
