Numbers 35:15; Numbers 35:25; Numbers 35:28

15 These six cities shall be for refuge for the people of Israel, and for the stranger and for the sojourner among them, that anyone who kills any person without intent may flee there.

25 And the congregation shall rescue the manslayer from the hand of the avenger of blood, and the congregation shall restore him to his city of refuge to which he had fled, and he shall live in it until the death of the high priest who was anointed with the holy oil.

28 For he must remain in his city of refuge until the death of the high priest, but after the death of the high priest the manslayer may return to the land of his possession.