Deuteronomy 19:6-8

World English Bible

⁶ Otherwise, the avenger of blood might pursue the man slayer while hot anger is in his heart and overtake him, because the way is long, and strike him mortally, even though he was not worthy of death, because he didn’t hate him in time past. ⁷ Therefore I command you to set apart three cities for yourselves. ⁸ If Yahweh your God enlarges your border, as he has sworn to your fathers, and gives you all the land which he promised to give to your fathers;