Deuteronomy 19:5-7

New American Standard Bible

⁵ as when a person goes into the forest with his friend to cut wood, and his hand ^[a]swings the axe to cut down the tree, and the iron head slips off the ^[b]handle and ^[c]strikes his friend so that he dies—he may flee to one of these cities and live. ⁶ Otherwise, the avenger of blood might pursue ^[d]him ^[e]in the heat of his anger, and overtake him because the way is long, and ^[f]take his life, though he was not sentenced to death since he had not hated him previously. ⁷ Therefore I command you, saying, ‘You shall set aside for yourself three cities.’