Joshua 20:1-4

Then the LORD said to Joshua, “Say to the people of Israel, ‘Appoint the cities of refuge, of which I spoke to you through Moses, that the manslayer who strikes any person without intent or unknowingly may flee there. They shall be for you a refuge from the avenger of blood. He shall flee to one of these cities and shall stand at the entrance of the gate of the city and explain his case to the elders of that city. Then they shall take him into the city and give him a place, and he shall remain with them.