Leviticus 25:29-33

‘Likewise, if a man sells a dwelling house in a walled city, then his redemption right remains valid until a full year after its sale; his right of redemption lasts a full year.

But if it is not bought back for him within the space of a full year, then the house that is in the walled city passes permanently to its purchaser throughout his generations; it does not revert in the jubilee.

The houses of the villages, however, which have no surrounding wall, shall be regarded as open fields; they have redemption rights and revert in the jubilee.

As for the cities of the Levites, the Levites have a permanent right of redemption for the houses of the cities which are their possession.

What, therefore, belongs to the Levites may be redeemed, and a house sale in the city of this possession reverts in the jubilee, because the houses of the cities of the Levites are their possession among the sons of Israel.