TSK · Numbers 35:12

The avenger of blood shall himself put the murderer to death: when he meeteth him, he shall put him to death.

lest the avenger of blood pursue the manslayer, while his heart is hot, and overtake him, because the way is long, and smite him mortally; whereas he was not worthy of death, inasmuch as he hated him not in time past.

that the manslayer that killeth any person unwittingly [and] unawares may flee thither: and they shall be unto you for a refuge from the avenger of blood.

And, behold, the whole family is risen against thy handmaid, and they say, Deliver him that smote his brother, that we may kill him for the life of his brother whom he slew, and so destroy the heir also. Thus will they quench my coal which is left, and will leave to my husband neither name nor remainder upon the face of the earth.