Deuteronomy 19:4-6

Thomson(i) 4 And this shall be the ordinance for every slayer who may flee thither, and live. Whosoever shall smite his neighbour unawares, and hated him not in times past, 5 for instance whosoever shall go with his neighbour into the forest to collect wood, and the hand of him who is cutting the wood with an axe being drawn back, the iron shall slip from the helve, and accidentally fall on his neighbour, and he die; such a one shall flee with speed to one of the cities, and live. 6 Lest the avenger of blood pursuing, because his heart is inflamed, should overtake him, if the way be too long, and slay him, though he is not guilty of death, because he hated him not in time past;