Joshua 20:3-6

3so that anyone who kills a person accidentally and unintentionally may flee there and find protection from the avenger of blood. 4When they flee to one of these cities, they are to stand in the entrance of the city gate and state their case before the elders of that city. Then the elders are to admit the fugitive into their city and provide a place to live among them. 5If the avenger of blood comes in pursuit, the elders must not surrender the fugitive, because the fugitive killed their neighbor unintentionally and without malice aforethought. 6They are to stay in that city until they have stood trial before the assembly and until the death of the high priest who is serving at that time. Then they may go back to their own home in the town from which they fled.”