Joshua 20:3-6

3 so that anyone who kills a person accidentally and unintentionally may flee there and find protection from the avenger of blood.

4 “When he flees to one of these cities, he is to stand in the entrance of the city gate and state his case before the elders of that city. Then they are to admit him into their city and give him a place to live with them.

5 If the avenger of blood pursues him, they must not surrender the one accused, because he killed his neighbor unintentionally and without malice aforethought.

6 He is to stay in that city until he has stood trial before the assembly and until the death of the high priest who is serving at that time. Then he may go back to his own home in the town from which he fled.”