Parashas Behar · Aliyah 5 · Passuk 25:32
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra (Torat Kohanim).
English: “The houses of the cities of their holding.” And not the houses of the cities of refuge.
Classical derasha (Sifra).
The perpetual redemption right applies to the ordinary Levitical cities of their inheritance, not to the cities of refuge as such.