Joshua 20:1-4

And Jehovah spake unto Joshua, saying, Speak to the children of Israel, saying, Assign you the cities of refuge, whereof I spake unto you by Moses, 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 he shall flee unto one of those cities, and shall stand at the entrance of the gate of the city, and declare his cause in the ears of the elders of that city; and they shall take him into the city unto them, and give him a place, that he may dwell among them.