פירוש על בבא בתרא 6:7

מי שהיתה דרך [הרבי'] עוברת בתוך שדהו – the masses always presumed to be able to pass through there.

If a public path passed through a man’s field and he took it and gave them [another path] by the side of the field, what he has given he has given and what he has taken for himself does not become his.
A private path is four cubits. A public path is sixteen cubits. The king’s path has no prescribed measure. The path to a grave has no prescribed measure. The halting places, according to the judges of Tzippori, should be four kab’s space of ground.
Mishnah seven deals with laws concerning the building and the selling of private and public paths.
In the scenario presented in section one a person had a path that passed through the middle of his field and decided that he would take that path and use it as part of his field and he would create a different public path on the side of his field. According to the mishnah the seizure of the public path is invalid and the public may continue to use the path in the middle of the field. In addition, the path given on the side of the field becomes public property, such that the public may also use that path.
The remainder of the mishnah standardizes the sizes of paths for the purposes of selling and buying. A private path is four cubits (about 2 meters) wide and a public path is 16 cubits (8 meters) wide. Therefore if a person were to sell a private path he would be selling a four cubit path, and if he sold a public path he would have sold a 16 cubit path. The mishnah additionally informs us that a king’s procession passing through another person’s field is permitted to take as wide of a path as needed. So too, if a funeral procession passes, the procession may cut as wide of a path as needed. Finally, we learn that halting places, which were places on the path of the funeral procession, where the mourners would stop in the course of a funeral procession in order to eulogize the dead, were generally four kab big (25 meters by 17 meters). If a person sold a “halting place” to another person this is the size of the land sold.

ושלו לא הגיעו – but the many have two paths, for we hold that a narrow path marking the boundary that the masses presumed [to use], it is forbidden to ruin.

דרך היחיד – a person who sells to his fellow a path within his field needs to give him four cubits.

דרך המלך אין לו שעור – for the king breaches a fence in front of him to make for himself a path.

דרך הקבר – when they carry the dead person to his grave, there is no measure. It is an enactment of the Sages because of the dignity of the deceased, but they are not able to breach a fence like the way of the king, but those who accompany the dead can pass ove seeds and the don’t have to turn to the one side or the other.

בית ארבעה קבים – it is [thirty three cubits and two handbreadths] wide at the length of fifty cubits. And the funeral-halting place where they would make seven halts of the funeral escort on returning from burial for lamentation or consolation, corresponding to the seven mentions of הבל/vanity in at the beginning of the [Biblical] book of Ecclesiastes.