Deuteronomy 19:11 - 19:13
11 “But if there is a man who hates his neighbor and lies in wait for him and rises up against him and strikes down his life so that he dies, and he flees to one of these cities, 12 then the elders of his city shall send and take him from there and give him over into the hand of the avenger of blood, that he may die. 13 You shall not pity him, but you shall purge the blood of the innocent from Israel, that it may go well with you.