Deuteronomy 19:4-6

New Catholic Bible

⁴ This is the regulation concerning the one who has killed another and flees there to save his life: one who kills his neighbor unintentionally, who did not previously bear him ill will, ⁵ for example, when a man goes into the woods with his neighbor to cut wood, and as he is swinging the ax to cut down a tree, and the head of the ax flies off and kills the neighbor. That man may flee to one of the cities to save his life. ⁶ Otherwise, the relative who seeks blood vengeance might seek him out while he is still blind with rage, and if the distance be too great he would then be able to catch up with him and kill him even though he did not really deserve to die since he did not bear the man any previous ill will.^[a]