Numbers 35:25-28

25The assembly is to protect the one who kills someone from the avenger of blood. Then the assembly will return him to the city of refuge he fled to, and he must live there until the death of the high priest who was anointed with the holy oil.

26“If the one who kills someone ever goes outside the border of the city of refuge he fled to,

27and the avenger of blood finds him outside the border of his city of refuge and kills him, the avenger will not be guilty of bloodshed,

28for the one who killed a person was supposed to live in his city of refuge until the death of the high priest. Only after the death of the high priest may the one who has killed a person return to the land he possesses.