Numbers 35:9-12

9Then the Lord spoke to Moses, saying,

10“1Speak to the sons of Israel and say to them, ‘When you cross the Jordan into the land of Canaan,

112then you shall select for yourselves cities to be your 3cities of refuge, so that the one who commits manslaughter by 4killing a person 5unintentionally may flee there.

126The cities shall 7serve you as a refuge from the avenger, so that the one who commits manslaughter does not die until he stands before the congregation for 8trial.