Rashi notes that concerning Hashem’s promise that Avraham Avinu would have offspring, the Patriarch did not request a sign, while regarding the promise of the Land, he did ask for a sign from Hashem asking: Bamah eida, “How shall I know?” Horav Yeruchem Levovitz, zl, explains this based upon a deeper understanding of the meaning of emunah, loosely translated as faith in Hashem. I say “loosely translated,” because faith and emunah are not identical. Faith is belief without proof, it’s more of a strong hypothesis, while emunah is much more profound. It is experiential. Emunah is derived from the word emes, which means truth. Truth is an absolute – so is emunah. Emunah stands in direct opposition to human logic. Indeed, as Horav Yitzchak Moshe Erlanger, Shlita, explains, it is a deliberate, conscious rejection of logical reasoning. Emunah ranks above and beyond the logical plane; the concept can only be explored and understood on a spiritual level. Emunah, according to the Maharal, is the key to our closeness with Hashem. The Baal Shem Tov likewise said that, “Emunah is deveikus, clinging to Hashem.” It is the ultimate link between the Creator and His creations.
Rav Yeruchem views emunah as k’munach b’kufsa, “it is laying in the box.” The maamin, believer, views his belief as a fait accompli, already done and carried out. So certain is he of Hashem’s taking care of the issues which demand belief – i.e. everything! When Hashem assured Avraham of offspring, he did not question Him. Hashem’s promise means that it is a done deal. He is already a father. Mazel tov! Concerning Eretz Yisrael, however, there were external variables, conditions that had to be met. It was conditional on his righteousness and that of his offspring. He feared his own unworthiness and the possibility of his descendants falling into sin, which would make him unworthy to retain the Land. This is why his emunah had a question attached to it. Too many things could go wrong. He sought assurance.