Deuteronomy 19:6-9

New Century Version

⁶ Otherwise, the dead person’s relative who has the duty of punishing a murderer might be angry and chase him. If the city is far away, the relative might catch and kill the person, even though he should not be killed because there was no intent to kill his neighbor. ⁷ This is why I command you to choose these three cities.

^8-9 Carefully obey all these laws I’m giving you today. Love the Lord your God, and always do what he wants you to do. Then the Lord your God will enlarge your land as he promised your ancestors, giving you the whole land he promised to them. After that, choose three more cities of safety