Deuteronomy 19:6-8

Evangelical Heritage Version

⁶ Otherwise, the avenger of blood might pursue the one who has killed someone, because the avenger is hot with anger. Then because of the long distance to the city of refuge, the avenger may overtake the man and strike him down fatally. His death would not be just, because he had not been hateful toward the other one beforehand. ⁷ Therefore I am commanding you this: Set aside for yourselves three cities.

⁸ When the Lord your God expands your territory, as he swore to your fathers, and he gives you the entire land that he promised to give your fathers,