Leviticus 25:32; Leviticus 25:33

32 Notwithstanding the cities of the Levites, and the houses of the cities of their possession, may the Levites redeem at any time.

33 And if a man purchase of the Levites, then the house that was sold, and the city of his possession, shall go out in the year of jubile: for the houses of the cities of the Levites are their possession among the children of Israel.