Numbers 35:6

35:6 Now from these towns that you will give to the Levites you must select six towns of refuge to which a person who has killed someone may flee. And you must give them forty-two other towns.

Numbers 35:15

35:15 These six towns will be places of refuge for the Israelites, and for the foreigner, and for the settler among them, so that anyone who kills any person accidentally may flee there.