Deuteronomy 19:8-10

8“And if the Lord your God 1enlarges your territory, just as He has sworn to your fathers, and gives you all the land that He 2promised to give your fathers-- 9if you 3carefully follow all of this commandment which I am commanding you today, 4to love the Lord your God, and to walk in His ways always--5then you shall add three more cities for yourself, besides these three. 10So innocent blood will not be shed in the midst of your land which the Lord your God is giving you as an inheritance, and 6guilt for bloodshed will not be on you.