Leviticus 25:32-34

32Nevertheless the cities of the Levites, the houses of the cities of their possession, may the Levites redeem at any time. 33And if one of the Levites redeem, then the house that was sold, and the city of his possession, shall go out in the jubilee; for the houses of the cities of the Levites are their possession among the children of Israel. 34But the field of the suburbs of their cities may not be sold; for it is their perpetual possession.