Deuteronomy 4:41-43
41
Cities of Refuge
Then Moses set aside three cities east of the Jordan,
42 to which anyone who had killed a person could flee if he had unintentionally killed his neighbor without malice aforethought. He could flee into one of these cities and save his life.
43 The cities were these: Bezer in the desert plateau, for the Reubenites; Ramoth in Gilead, for the Gadites; and Golan in Bashan, for the Manassites.