Halakhah su Levitico 25:30

And that which our Rabbis, may their memory be blessed, also said (Arakhin 31b) that if the [last] day of the twelfth month arrives and [the original owner] does not find the buyer [to redeem it from him, behold he places his money in the court, breaks the door of the house and enters; and when the buyer comes,] he comes and takes his money. And that which they said (Arakhin 31b) that one who sells a house in the walled cities and the Jubilee arrives in the midst of the year of the sale, it does not go back immediately with the [start of the] Jubilee, but its law is like in other years in the years of the Jubilee [cycle] - that it is finalized with the [end of the] year if the seller does not want to redeem it. And that which they said (Arakhin 33a) [regarding] the seller of a house in the open cities - that if he wants, he can redeem [it] immediately like the law of a house from the houses of walled cities; and if does not want to redeem [it] immediately, he can redeem it even after a year like the law of fields. As they have the better power of [both] the fields, and the houses of the walled cities. And that which they said (Arakhin 32a) that the law of everything that is inside the wall, such as gardens, bathhouses, and birdhouses, is like the law of houses - as from that it is written (Leviticus 25:30), "that is in the city," it includes it all. But if there were fields inside the city, their law is like fields outside of the city, as it is stated, "the house will be established" - meaning to say, the house and all that is similar to a house, such as bathhouses, and birdhouses and even orchards, but not fields. And a house that does not have four ells by four ells is not called a house; and therefore, it is not finalized. And a house is not finalized in Jerusalem. And a city that its roofs are its walls does not have the status of of one surrounded by a wall, but rather we require that it has a wall besides its roofs. And we also require that it was first surrounded and settled afterwards, but if it was settled [first] and surrounded afterwards, that is not a walled city. And we only rely upon a wall that surrounded [a city] from the time that Yehoshua conquered the Land. And once they were exiled in the first destruction [of the Temple], the holiness of a walled city was nullified. But when Ezra came in the second coming [to the Land of Israel], all of the cities surrounded by walls at that time were sanctified; since their coming in the the time of Ezra which was the second coming, was like their coming in the time of Yehoshua: Just like their coming in the time of Yehoshua [provided that] they counted the sabbatical years and Jubilees, the walled cities were sanctified and they become obligated in the tithe; so too at the time of Ezra was it so. And so too, when the messiah will come with the third coming, we will begin to count the sabbatical years and Jubilees, the houses of walled cities that will be surrounded at that time will be sanctified and every place that will be conquered will be obligated in tithes. As it is stated (Deuteronomy 30:5), "And the Lord, your God, will bring you, etc." - and they said (Arakhin 32b), "It compares your inheriting to the inheriting of your ancestors, etc." And the rest of its details are elucidated in Tractate Arakhin (see Mishneh Torah, Laws of Sabbatical Year and the Jubilee 12).