'Slayer' in the Bible

“Now this is the case of the offender (manslayer) who may escape there and live [protected from vengeance]: when he kills his neighbor unintentionally, not having hated him previously—

otherwise the avenger of blood might pursue the offender in the heat of anger, and overtake him, because it is a long way, and take his life, even though he did not deserve to die, since he did not hate his neighbor beforehand.