Deuteronomy 19:6; Deuteronomy 19:12

6 lest the avenger of blood in hot anger pursue the manslayer and overtake him, because the way is long, and strike him fatally, though the man did not deserve to die, since he had not hated his neighbor in the past.

12 then the elders of his city shall send and take him from there, and hand him over to the avenger of blood, so that he may die.