At the beginning of Bereishis, Rashi quotes Rabbi Yitzchok’s statement, “The Torah should have begun with the mitzvah of proclaiming the new month, the first mitzvah given to Israel. Why then does it start with Bereishis? … So that the nations should not say, ‘You are robbers…’” The Kli Yakar asks: Is this a reason to change the order of the Torah? He answers that such an accusation would lead to atheism, for they would say, “There is no justice and no Judge, and whoever is stronger prevails."
[Here is the full quote from the Kli Yakar:
: So what if they accuse us of being robbers? Is that so important that it warrants a change in the order of the Torah? The answer is that the accusation of robbery would lead to a complete denial of G-d, for they will say, “There is no justice and no Judge, and whoever is stronger prevails. For if the world had a Manager, who takes care of all that goes on, why did He not stop you when you took the land of the Seven Nations by force and by robbery?
Presumably the Kli Yakar means that the rest of the Torah from Shemos and onward, which says that Hashem not only let us take over Eretz Yisroel but actually commanded us to do so and intervened to help us, would not satisfy these people, for they would not accept a G-d who could condone such an injustice, and therefore they would either deny His existence or refuse to worship Him.]
He writes at length on this subject and then adds that when Rabbi Yitzchok said that the Torah should have begun with the mitzvah of proclaiming the new month, he does not mean that the Torah did not have to write the story from Bereishis up to the mitzvah of the new month at all. Of course there is a great need to know about the world’s creation, and many other fundamental subjects in the book of Bereishis. Rather, the question is that since the main purpose of the Torah is its commandments, it should have begun with the first mitzvah and told the story of creation later on. The answer is that writing it that way would have left the door open for sinners to deny the Torah [because they might not read the entire Torah; they might stop after the first mitzvah and say, how could Hashem have given all these mitzvos in which He warns us against theft (for example, taking the Pesach offering from our own sheep) if He did not stop you from committing theft?]. Therefore the Torah placed the story of creation first in order to teach that they did not take the land by robbery. See his entire lengthy discussion of this.
Now, we can debate about whether he is correct that any sort of robbery leads to heresy. It is well known that Hashem granted man free will. Robbery is no different from any other sin, an act which is against Hashem’s will, yet we have free will to commit it, and Hashem does not intervene to stop us.
However, in this particular case, the conquest of Eretz Yisroel and freeing ourselves from exile, his words are very true, for those matters are in the hands of Hashem alone, reinforced with His oath. [Therefore, the nations could argue that if G-d exists, although He does not intervene to stop injustice, He should have intervened to stop you from conquering Eretz Yisroel, since the exile and redemption of the Jewish people are solely in His hands.
It is unclear how they nations were to assume that the exile and redemption of the Jewish people should be only in the hands of Hashem.]