Numbers 35:25-27

MKJV(i) 25 And the congregation shall deliver the one who kills out of the hand of the revenger of blood. And the congregation shall send him back to the city of his refuge, to which he had fled. And he shall stay in it until the death of the high priest who was anointed with the holy oil. 26 But if the one who killed shall at any time come outside the border of the city of his refuge to which he had fled, 27 and if the avenger of blood finds him outside the borders of the city of his refuge, and if the avenger of blood kills the slayer, he shall not be guilty of blood,