Numbers 35:22-25

22“ ‘But if without enmity someone suddenly pushes another or throws something at them unintentionally 23or, without seeing them, drops on them a stone heavy enough to kill them, and they die, then since that other person was not an enemy and no harm was intended, 24the assembly must judge between the accused and the avenger of blood according to these regulations. 25The assembly must protect the one accused of murder from the avenger of blood and send the accused back to the city of refuge to which they fled. The accused must stay there until the death of the high priest, who was anointed with the holy oil.