Does this mean that a woman is forbidden to marry into a different tribe than that of her father?
Rashi (in Bamidbar 27:7), Ramban #2 and Targum Yonasan: the prohibition of marrying into a different tribe ("Lo Sisov Nachalah") 1 was restricted to that generation, to the B'nos Tz'lofchad. 2
Why was the Torah not similarly concerned regarding an heiress who was already married, or a woman whose father or brothers would die leaving behind no children after she was already married?
Ramban #1: The Torah was only concerned about something that was rectifiable, which those cases were not. And it did not want to change the Dinim of inheritance in such a case by prohibiting her husband or her son from inheriting her.
Ramban #2 (citing Bava Basra, 120a): The B'nos Tz'lofchad was the only case in that generation where daughters inherited, which explains why they were the only family to lodge a complaint. and did not speak about a general case where a man died, leaving no sons.
Ramban #3: Pasuk 5 and Pasuk 6 are talking about two different Mitzvos 1 : Pasuk 5 is a prohibition against the B'nos Tz'lofchad marrying into a different tribe, whereas Pasuk 6 is a prohibition against the husband and sons inheriting the property of a woman from a different tribe who became an heiress. 2
Why did the Torah not extend the La'av of "Lo Sisov Nachalah" to future generations?
Ramban: The Torah was only concerned that the portions of the tribes should not get mixed up even as they were dividing the land. 1
Ramban: And it extended it to the whole generation because the exact time of distribution was not yet known.
Why did the Torah not extend the La'av of "Lo Sisov Nachalah" to future generations?
