The First Rashi.
Bereishit (Genesis 1:1-6:8 )
"Rebbe Yitzchak said, '[God] need only have begun the Torah from 'This month shall be to you" which is the first Commandment which Israel was commanded. For what reason did it begin with 'Bereishit'?... So that if the nations of the world will say to Israel, 'You are bandits, for you conquered the lands of the seven nations' Israel will say to them, 'The whole earth belongs to the Holy One, Blessed is He; He created it and He gave it to the one found proper in His eyes. By His wish He gave it to them, and by His wish He took it from them and gave it to us.'" (Rashi, Bereishit 1:1)
Rashi opens his monumental commentary on the Torah, quoting Rebbe Yitzchak,(1) who tells us that the Torah should have begun with the first mitzvah of sanctifying the new moon, and it only opened with the story of Creation and the subsequent events in order to teach us that the Jewish people have a God-given right to the land of Israel. The commentators ask why this point is so significant to the extent that the order of the Torah is drastically changed because of it.(2)
The Levush Haorah(3) answers that if it is true that the Jewish people stole the land of Eretz Yisrael then the whole Torah is undermined because in the Torah there are mitzvot prohibiting stealing and of encroaching on the property of another person (hasagat gevul). Accordingly, the nations of the world will say that the Jews who claim to follow the Torah do not keep to its commands because they stole the land from the Seven Canaanite nations. And if the Jewish people will answer that God allowed them to steal it from the nations, then that is even more problematic as it demonstrates that even God Himself, does not, so to speak, observe His own commandments such as 'do to not steal' and hasagat gevul. This would cause a great Chillul Hashem (desecration of God's name) and undermine the whole message of the Torah.
Rebbe Yitzchak explains that the Torah addresses this argument, saying that there is no thievery here at all as God created the whole world and He determines who owns which land; It was His will that the nations have it at first, and it was His decision to take it from them and give it to the Jewish people.
The Levush Haorah teaches us a fundamental lesson with this explanation; Chillul HaShem is so serious that it is necessary to alter the nature of the Torah in order to avoid this possibility. This is because the whole purpose of Creation is Kiddush HaShem, the sanctification of God's name, the antithesis of Chillul HaShem. This is expressed in Pirkei Avos: "Everything that the Holy One, Blessed be He, created in His world, He only created for His honor." (4) The Mishna is teaching us the purpose in our lives should be to elevate God in the eyes of the world.(5) The exact opposite of this is Chillul HaShem - acting in such a way that causes people to see the Torah or the Creator in a negative light, That is why it is so important that the Torah immediately assert the God-given right of the Jewish people to own Eretz Yisrael. Thus the Torah begins with a vital message for all of us - just like God is extremely careful to be seen to be consistent with His Torah, so too we must be careful that our actions also be consistent with the mtzvot of the Torah.
1. Who, according to some commentaries, is Rashi's own father, see Sifsei Chachamim, 1:1, dh: Amar Rebbe Yitzchak.
2. Some commentaries take Rashi literally to mean that the Torah should not have included all the stories of Bereishis and the beginning of Shemos and instead began with the Mitzvos. Sifsei Chachamim (dh: deha), explains that the primary point of the Torah is to teach us the Mitzvos, and these stories should have been compiled in another sefer, like the books of the Prophets. Other commentators argue that Rebbe Yitzchak did not mean that these events should not be in the Torah at all, rather that they should have come at a later point (see Nachalas Yaakov).
3. Bereishis, 1:1. Written by Rav Mordechai Yaffe zt"l, who is most well known as the author of of the Levush, a commentary on the Shulchan Aruch.
4. Pirkei Avos, 6:11.
5. This does not contradict the Mesillas Yesharim who says that HaShem created us for our good. That is, as far as we can understand, the reason that HaShem created us since He has no needs. The Mishna in Avos is telling us how to attain the greatest good - by giving HaShem honor in the world.