Numbers 35:12-19

12You will have the cities as a refuge from the avenger, so that the one who kills someone will not die until he stands trial before the assembly.

13The cities you select will be your six cities of refuge.

14Select three cities across the Jordan and three cities in the land of Canaan to be cities of refuge.

15These six cities will serve as a refuge for the Israelites and for the alien or temporary resident among them, so that anyone who kills a person unintentionally may flee there.

16“If anyone strikes a person with an iron object and death results, he is a murderer; the murderer must be put to death.

17If anyone has in his hand a stone capable of causing death and strikes another person and he dies, the murderer must be put to death.

18If anyone has in his hand a wooden object capable of causing death and strikes another person and he dies, the murderer must be put to death.

19The avenger of blood himself is to kill the murderer; when he finds him, he is to kill him.