Why does blood need to be put on the mercy seat In Leviticus 16:14-15 it says:


  And he shall take some of the blood of the bull and sprinkle it with
  his finger on the front of the mercy seat on the east side, and in
  front of the mercy seat he shall sprinkle some of the blood with his
  finger seven times. Then he shall kill the goat of the sin offering
  that is for the people and bring its blood inside the veil and do with
  its blood as he did with the blood of the bull, sprinkling it over the
  mercy seat and in front of the mercy seat.


I understand that sin leads to death and so forgiveness of sin comes through a sacrifice (something or someone dying in our place), however why is Aaron instructed to sprinkle the blood on the mercy seat? How does this point back to Jesus?

I'm looking for an Evangelical view
This practice of sprinkling the altar reminds the people of the blood of Jesus. Yes Jesus died, but when the Jews saw the blood, it reminded them of the huge, very real sacrifice Jesus would have to pay when He came. Goat blood on the actual altar, Jesus' blood on the altar of the cross.