Our parsha opens with the possuk, "Go forth from your land...to the land asher arehkho (usually translated- that I will show to you). Zera Shimshon asks two questions. Firstly, if Hashem meant to tell Avram that he should go to a land that Hashem will show him, like its usual meaning, it is more fitting to write "asher ereh lecha". Secondly, in truth we don't find Hashem told Avram to go to Eretz Yisroel! It is only written (possuk 5), "And Avram took Sarah his wife... and they left to go to the Land of Kanaan". The possuk does not mention that Hashem told him to go there; it implies that Avram understood this by himself. How did Avram realize that this was the land Hashem intended for him to go to?
Zera Shimshon explains in light of the Medrash (Yalkut Shimoni Vayairo remmez 102) that explains the origin of the name "Yerushalayim". The Medrash explains that Avram Avram called it "Har Yayroeh" and Shaim (the son of Noach) called it Shalaim. Hashem combined both of these names, contracted them, and called it Yerushalayim.
The commentator on the Yalkut asks why did Shaim and Avram call it two different names? What is the depth in each of these names?
He explains that Shaim called it Shalaim, which means complete, because he was able to perceive the completeness of Hashem's physical world; health, strength, and prosperity that manifested itself in Yerushalayim. However he was not on such a high level of spirituality to bring out the spirituality that also exists in Yerushalayim. Avram on the other hand, who was on a much greater level of spirituality, also brought out the tremendous spiritual beauty of Eretz Yisroel in general, and specifically Yerushalayim. Therefore, he called it Har Yeiroeh, which has the same root as Yiras Hashem.
Hashem called it both of these names because in truth both exist there; great spirituality, for those who can be aware of it, and also great plenty for those who are not at that level.
From here, continues Zera Shimshon, we see that Eretz Yisroel is different from other lands. The quality, beauty and splendor of all lands are independent of the character and conduct of its inhabitants. However the spiritual and physical beauty of Eretz Yisroel is connected and proportionate to its inhabitants conduct. When there are tzaddikim there, for instance Shaim, then it’s physical beauty is seen. And when there are even greater tzaddikim there, like Avraham Avinu, then even its spiritual glory can be felt.
According to this, Zera Shimshon explains, the reason it is written asher arehko which literally means "that I showed you (to others)" is because when people see the beauty of Eretz Yisroel they will realize that it is because of the righteousness of Avraham, and his righteousness will be made known to all.
This is also the way Avram understood that he has to go to Eretz Kannan. Since Eretz Yisroel is the only land that reflects the spiritual level of its inhabitants and Hashem told Avram that his greatness will be shown, Avram put "two and two together" and understood that Hashem was referring to Eretz Kannan.
