Numbers 35:22-25
‘ However, if he pushes him suddenly without enmity, or throws anything at him without lying in wait,or uses a stone, by which a man could die, throwing it at him without seeing him, so that he dies, while he was not his enemy or seeking his harm,then the congregation shall judge between the manslayer and the avenger of blood according to these judgments.So the congregation shall deliver the manslayer from the hand of the avenger of blood, and the congregation shall return him to the city of refuge where he had fled, and he shall remain there until the death of the high priest who was anointed with the holy oil.
Deuteronomy 19:1-13
“ When the Lord your God has cut off the nations whose land the Lord your God is giving you, and you dispossess them and dwell in their cities and in their houses,you shall separate three cities for yourself in the midst of your land which the Lord your God is giving you to possess.You shall prepare roads for yourself, and divide into three parts the territory of your land which the Lord your God is giving you to inherit, that any manslayer may flee there.“ And this is the case of the manslayer who flees there, that he may live: Whoever kills his neighbor unintentionally, not having hated him in time past—as when a man goes to the woods with his neighbor to cut timber, and his hand swings a stroke with the ax to cut down the tree, and the head slips from the handle and strikes his neighbor so that he dies— he shall flee to one of these cities and live;lest the avenger of blood, while his anger is hot, pursue the manslayer and overtake him, because the way is long, and kill him, though he was not deserving of death, since he had not hated the victim in time past.Therefore I command you, saying,‘ You shall separate three cities for yourself.’“ Now if the Lord your God enlarges your territory, as He swore to your fathers, and gives you the land which He promised to give to your fathers,and if you keep all these commandments and do them, which I command you today, to love the Lord your God and to walk always in His ways, then you shall add three more cities for yourself besides these three,lest innocent blood be shed in the midst of your land which the Lord your God is giving you as an inheritance, and thus guilt of bloodshed be upon you.“ But if anyone hates his neighbor, lies in wait for him, rises against him and strikes him mortally, so that he dies, and he flees to one of these cities,then the elders of his city shall send and bring him from there, and deliver him over to the hand of the avenger of blood, that he may die.Your eye shall not pity him, but you shall put away the guilt of innocent blood from Israel, that it may go well with you.