Bilangan 35:31

35:31 Moreover, you must not accept a ransom for the life of a murderer who is guilty of death; he must surely be put to death.

Bilangan 35:33

35:33 “You must not pollute the land where you live, for blood defiles the land, and the land cannot be cleansed of the blood that is shed there, except by the blood of the person who shed it.