By Rabbi David Cohen: The Midrash (Rabbah 87:10) relates the following dialogue between Moshe and Hashem. Hashem said to Moshe, “You are grabbing the rope from both ends. (In other words, you cannot go forward, since you are pulling from both sides.) If you want to fulfill, ‘Let me now cross and see,’ then you cannot ask Me to forgive the nation. If you insist that I forgive them, then you cannot enter into the Land.” This Midrash needs an explanation. How would the nation’s forgiveness affect Moshe’s entering the Land and vice versa?
Horav Moshe Bick, zl, explains that Moshe’s request that the nation be absolved for the sin of the spies and their inappropriate reaction to the misinformation they received ran counter to his request that he be granted entry into the Land. There is a rule that tzaddik gozeir v’HaKadosh Baruch Hu mekayeim, the righteous decree and Hashem carries out their wish. Hashem would, therefore, have listened to Moshe’s request concerning the nation. This rule applies, however, only under such circumstances that the tzaddik does not derive personal benefit from his plea. If he has a vested interest, either directly or even indirectly, the plea will not be effective. The reason for this is that the tzaddik serves as a tzinor, pipe, conduit, through which Hashem delivers His beneficence. For the tzaddik to be a conduit, no obstruction can prevent the smooth delivery of the Heavenly blessings. Thus, once the tzaddik takes for himself, the conduit becomes obstructed, and his decree is less effective.
When Moshe prayed to Hashem to allow him to enter the Land, it was a personal plea, a personal prayer. This precluded his speaking on behalf of the nation. Thus, Hashem told him: If you go, they cannot, and, if they go, you cannot. In order for Me to grant them absolution, you must defer entering Eretz Yisrael. Therefore, he told the nation, “Hashem became angry with me. I lost out because of you. The only reason that I did not enter the Land was that, had I gone, you would not.” This is but one other case in which Moshe, our quintessential leader, sacrificed for the nation.