Deuteronomy 19:7-9

New Catholic Bible

⁷ This is why I command you to set aside three cities for yourselves.

⁸ If the Lord, your God, adds to your territory, as he promised to do to your ancestors, and he gives you all the land that he promised to give to your fathers, ⁹ for you have carefully observed all the commandments that I have given you today, to love the Lord, your God, and always walk in his ways, then you will set aside another three cities beside the first three.