Musar su Salmi 111:6

Let us turn our attention to the statement of Rabbi Yitzchak quoted by Rashi in his first commentary on the first verse. Rabbi Yitzchak says that the Torah did not really have to commence prior to the twelfth chapter of Exodus when the commandment to sanctify the New Moon is given to the people of Israel. He goes on: "ומה טעם פתח בבראשית, משום כח מעשיו הגיד לעמו, לתת להם נחלת גוים, "what is the reason that G–d commenced the written Torah with the story of Bereshit?, It is to tell us that G–d revealed to His people His powerful works, in giving them the heritage of nations." (Psalms 111,6) The commentator elaborates that if the nations of the world would challenge Israel's right to the land of Israel accusing Israel as having illegally dispossessed its seven Canaanite nations, Israel could reply that since the earth belongs to G–d seeing He has created it, He is free to give any part of it to anyone He chooses. Since Israel found favor in His eyes, G–d gave that land to Israel. This premise raises a major question, as do the repeated words "when He wanted to, He gave it to them, and when He wanted to, He gave it to us." What kind of justice is it to give someone a gift only to revoke the gift at a later stage, especially when such gift has become a נחלה, an inheritance, i.e. something inviolable?