Hebrews 9:16-18

16Think about this. A person may make an agreement about who will receive his things after his death. But nobody receives anything until it is clear that the person has really died.

17The agreement only has authority after the death of the person who made it. It has no authority while that person is still alive.

18So even God's first agreement with his people needed the blood of an animal. The agreement only had authority after a death.