Deuteronomy 19:2-9

2you shall separate three cities for yourself in the midst of your land which the Lord your God is giving you to possess.

3You shall prepare roads for yourself, and divide into three parts the territory of your land which the Lord your God is giving you to inherit, that any manslayer may flee there.

4“And this is the case of the manslayer who flees there, that he may live: Whoever kills his neighbor unintentionally, not having hated him in time past—

5as when a man goes to the woods with his neighbor to cut timber, and his hand swings a stroke with the ax to cut down the tree, and the head slips from the handle and strikes his neighbor so that he dies—he shall flee to one of these cities and live;

6lest the avenger of blood, while his anger is hot, pursue the manslayer and overtake him, because the way is long, and kill him, though he was not deserving of death, since he had not hated the victim in time past.

7Therefore I command you, saying, ‘You shall separate three cities for yourself.’

8“Now if the Lord your God enlarges your territory, as He swore to your fathers, and gives you the land which He promised to give to your fathers,

9and if you keep all these commandments and do them, which I command you today, to love the Lord your God and to walk always in His ways, then you shall add three more cities for yourself besides these three,