Moshe, b'not Tzelofchad, and the details of the Law
Most kids who go to day school know the story of the daughters of Tzelofchad, part one of which is in this last week's parsha, and part two is at the end of Ma'asei. However, a careful reading of the peshat tells us a lot about Hashem's law and how it is applied. The problem: Even Divine law can't account for every single possible situation in one or two sentences. For example " Do Not Kill" seems to be straightforward. However, what about someone who is coming to kill you? can you kill them? what about war? That one sentence doesn't cover all the eventualities. We apply the Divine rules to situations as they come up.
The daughters of Tzelofchad, who was dead, wanted to take part in the inheritance of the land, which was declared to be for the male head of the household. Since there was no male head of their household, they were being left out. Moshe brings their case to God. The reply from God comes in the form of "vayomer Hashem el Moshe laymor." The classic, "God spoke to Moshe saying....." and proceded to set out rules for daughters to inherit the land of their fathers when there weren't any sons. God also sets out rules for how the extended family inherits, a sort of heirachy.
At the end of Ma'asei, the elders of the tribe of Menashe(the tribe of Tzelofchad and his daughters) complain to Moshe that, should the daugters who own land marry someone of a different tribe, the land will eventually become the property of that other tribe(because the land will be inherited by male children who will by definition be members of that other tribe), and the land of Menashe will diminish. In this case, the Torah doesn't record Moshe going to Hashem and asking a question. Instead the wording is "Va'Yitzav Moshe et b'nai Yisrael al pi Hashem lamor" Moshe instructed/commanded the children of Israel according to the word(lit. by the mouth) of Hashem saying: Ze hadavar asher tziva Hashem l'vnot Tzelofchad lamor- this is the word that Hashem commanded to the daughters of Tzelofchad saying.
In other words, Moshe doesn't go back and ask Hashem for the answer, like he did the first time. This time he instructs the people 'according to the word of Hashem.' Now, the believer can say that what that the words literally mean from the mouth of Hashem. However, it seems to me the common usage of al pi in Torah is that it does not denote a new utterance, but means consistant with or in accordance with a previous utterance. So, Moshe takes the rule that Hashem gave, and interprets it govern the circumstances that he is confronted with. Clearly what Moshe comes up with is not contained in the initial rule, or at least it wasn't written out, and the elders of Menashe obviously didn't know this new info, or they wouldn't have asked the question. We are left with the conclusion that Moshe derives the new rules on his own, based on his understanding of the previous utterence of God. And his solution is that women who want to maintain their inherited land have to marry someone from their own tribe. Ironically, the new rules serves to eliminate 11/12ths of the eligible men from the dance card of the daughters of Tzelofchad, or any other land owning woman who wants to maintain her ownership of that land.
What is my point? Firstly, we have(I think) the first instance of interpretation of what you could call Halacha to make it apply to a situation that was not obvious from the letter of the Law. Secondly, for the liberal in me, it shows how the Law of God can be interpreted, starting with the Word of God protecting the rights of women, and winding up with the words of man(albeit Moshe) restricting the rights of women(a theme expanded upon at length by R. Eliezer Berkowitz in Jewish Women in Time and Torah and to a lessor but still signficant extent by R. Y.H. Henkin in Equality Lost).