Numbers 35:30

26But if the slayer shall at any time come without the border of the city of his refuge, whither he was fled;

27And the revenger of blood find him without the borders of the city of his refuge, and the revenger of blood kill the slayer; he shall not be guilty of blood:

28Because he should have remained in the city of his refuge until the death of the high priest: but after the death of the high priest the slayer shall return into the land of his possession.

29So these things shall be for a statute of judgment unto you throughout your generations in all your dwellings.

30Whoso killeth any person, the murderer shall be put to death by the mouth of witnesses: but one witness shall not testify against any person to cause him to die.

31Moreover ye shall take no satisfaction for the life of a murderer, which is guilty of death: but he shall be surely put to death.

32And ye shall take no satisfaction for him that is fled to the city of his refuge, that he should come again to dwell in the land, until the death of the priest.

33So ye shall not pollute the land wherein ye are: for blood it defileth the land: and the land cannot be cleansed of the blood that is shed therein, but by the blood of him that shed it.

34Defile not therefore the land which ye shall inhabit, wherein I dwell: for I the Lord dwell among the children of Israel.