The Gemara in Shabbos (88b) relates, that when Moshe Rabbeinu ascended to heaven to receive the Torah, the malochim objected to Hashem: “What is man that You should remember him?” What is this earthly being doing here in heaven? How can you give him the Torah? He is material and the Torah is spiritual...”
A number of Meforshim explain, the malochim’s argument was based on the din in Choshen Mishpot (175) of bar metzrah (בר מצרא), a din which requires that if one wants to sell a piece of land, he must offer his neighbor first buying rights. This din is based on ועשית הישר והטוב - “One should do what is straight and good”. Since the malochim live in Shomayim, which is where the Torah is, they argued that they have more right to it then Klal Yisroel who are living far away?
The question is, why was the argument of the malochim not accepted? The din of bar metzrah is brought down halachah lemaseh in Shulchan Aruch, and everyone agrees to it?
Answers:
The Madanay Asher brings this question and he brings a number of answers:
1) The Shach (Choshen Mishpot 175:30) discusses a case when one sells land to his son, and then the neighbor comes and argues that he has first rights because of bar metzra. The Shach says, since the din of bar metzra is because of ועשית הישר והטוב - “One should do what is straight and good”, it makes sense that the son should come first, as it is fair and understandable that a father should sell land to his son. The Shach concludes that when it comes to selling to a son there is no din of bar metzra.
Based on this Shach, we can answer, that Klal Yisroel are considered sons of the Ribbono Shel Olam, and a son has first rights. Since the din of bar metzra doesn’t apply to a son, Klal Yisroel had more right to the Torah then the malochim. (The Chida in Pnei Dovid, Sifsei Maharash, Parshas Shavuos, and Divrie Yatziv, Pisgam al Shavuos pg. 211 all bring such an answer)
2) The Gemara in Bava Basra (5a) brings a story: Runya bought some land which was on the border of Ravina’s property. Ravina wanted to send him away because of the din of bar metzra (and he wanted the land). However, Rav Safra said that Runya was very poor, therefore, he should be left alone. Rashi explains, the din of bar metzra is because of ועשית הישר והטוב, and looking after a poor person also comes under ועשית הישר והטוב, therefore Rav Safra told Ravina to leave him alone. Rabbeinu Tam asks, “We don’t show mercy when it comes to din?”. However, Rashi isn’t bothered with this question. Seemingly, Rashi maintains that the din of bar metzra is a din which by its very nature involves being kind, therefore, although normally we don’t change dinim just because we want to have mercy, when it comes to the din of bar metzra we do.
Klal Yisroel without Torah were poor, they were no worse than the Runya in Bava Basra, therefore, the din of bar metzra never applied. (Divrei Yatziv, Yetziv Pisgam pg. 224)
3) The halachah is (175:54) that when it comes to giving presents the laws of bar metzra don’t apply. When it comes to giving presents there are no first rights, as a present by its very nature is only given to someone the giver wants to give it to. Torah was given to Klal Yisroel as a present, therefore, the dinim of bar metzra never applied. (Sifsei Maharash, Bereishis)
4) Klal Yisroel needed the Torah, as Torah is our life, and protects us from aveiros. Moreover, without Torah the world would cease to exist. However, for the malochim Torah is just a nice extra, however, they can survive without it. The dinim of bar metzra don’t apply, if the reason one wants the land is as an added extra (לרווחא דמילתא). Since for the malochim Torah is an extra, whereas for Klal Yisroel it is a necessity, the din of bar metzra doesn’t apply. (Sifsei Maharash)