What is the Torah adding here that is not included in the previous Pasuk?
Rashi: The Torah is teaching here, that, if the Gizbar of Hekdesh sells a field that a Levi declared Hekdesh, it reverts to the Levi in the Yovel. 1
Rashi (Rosh Hashanah, 29a): Even a house in a walled town, which does not revert to a Yisrael in the Yovel, reverts to a Levi.
Rashi: And does not go the Kohanim, like the field of a Yisrael, as the Pasuk states in 27:20.