Cities of refuge

Cities of refuge are the six cities that were designated by Moses at the command of God as locations to which Israelites could flee in order to be safe from retribution of other Israelites for offenses committed against others. Num. 35:9-16 gives a description of their purpose. In that culture the responsibility of retribution against a family member who had been killed or seriously injured rested on the "goel," the next of kin. The person was required to stay in the city until the death of the High Priest of that city (Num. 35:25-28). Then he was free to return to his home and retribution was not allowed upon him.

Note the typology: When the high priest dies, the offender is set free. In other words, when Jesus our High Priest died on the cross, we sinners were set free from sin.