Deuteronomy 4:42

that the manslayer might flee there , anyone who kills his neighbor unintentionally , without being at enmity with him in time past ; he may flee to one of these cities and save his life :

to which anyone who had killed a person could flee if they had unintentionally killed a neighbor without malice aforethought. They could flee into one of these cities and save their life.

That the slayer might flee thither, which should kill his neighbour unawares, and hated him not in times past; and that fleeing unto one of these cities he might live :