Deuteronomy 19:5

As when a man goeth into the wood with his neighbor to hew wood, and his hand fetcheth a stroke with the axe to cut down the tree, and the head slippeth from the helve, and lighteth upon his neighbor, that he die; he shall flee unto one of those cities, and live:

as when a man goes into the forest with his neighbor to hew wood, and his hand fetches a stroke with the axe to cut down the tree, and the head slips from the handle, and lights on his neighbor, so that he dies; he shall flee to one of these cities and live:

as when a man goeth into the forest with his neighbor to hew wood, and his hand fetcheth a stroke with the axe to cut down the tree, and the head slippeth from the helve, and lighteth upon his neighbor, so that he dieth; he shall flee unto one of these cities and live:

even he who cometh in with his neighbour into a forest to hew wood, and his hand hath driven with an axe to cut the tree, and the iron hath slipped from the wood, and hath met his neighbour, and he hath died -- he doth flee unto one of these cities, and hath lived,

If he goes into the forest with his neighbor to cut timber and swings his axe to chop down a tree, but the blade flies off the handle and strikes and kills his neighbor, he may flee to one of these cities to save his life.