Deuteronomy 19:6-8

Complete Jewish Bible

⁶ Otherwise the next-of-kin avenger, in the heat of his anger, may pursue the killer, overtake him because the distance [to the city of refuge] is long, and strike him dead — even though he didn’t deserve to die, inasmuch as he hadn’t hated him in the past. ⁷ This is why I am ordering you to set aside for yourselves three cities.

⁸ “If Adonai your God expands your territory, as he swore to your ancestors that he would, and gives you all the land he promised to give to your ancestors —