The Magid Meisharim, a collection of torah taught to the Bais Yosef by a malach (yes, I wrote that just to annoy pure rationalists), highlights three difficulties in the episode of the meraglim: 1) “Shlach” presents the idea of meraglim as an initiative of Moshe taken al pi Hashem, while the story as presented in Sefer Devarim sounds like Bnei Yisrael took the initiative in approaching Moshe and demanding the mergalim be sent (see Josh Waxman's post); 2) How could Moshe have sent spies to determine whether Eretz Yisrael is ‘ha-shemeina hi im raza’, is it fertile or not, when Moshe knew that Eretz Yisrael is ‘zvas chalav u’devash’ and under constant supervision by Hashem? 3) Moshe sent the spies to determine “if” the land was beautiful and easily conquered, implying there was a choice whether or not to go there. Moshe knew that Bnei Yisrael were destined to enter Eretz Yisrael – how could he have presented this as a matter of choice?
The Maggid explained to the Bais Yosef that because of the complaints of Bnei Yisrael there already was a decree over that generation not to merit entering the land. Despite the fact that they were not worthy, Hashem provided one last opportunity for the people to merit Eretz Yisrael – if they could prove their love for the land and desire to go there, the decree would be annulled. The episode of the spies was the final chance. Moshe was instructed “shlach”, give in to the people’s desire to send spies, encourage the spies to report on the land and its beauty, let the people start planning the conquest of the land, let them choose of their own volition to enter Eretz Yisrael, and in the merit of that great yearning, despite their many chataim, the gezeirah would be overturned and they would indeed merit entering the land. Tragically, even this final opportunity resulted in failure.
The sefer Eim HaBanim Smeicha quotes this teaching of the Magid Meisharim and adds the obvious mussar haskel. Our love and yearning for Eretz Yisrael has the power to overcome any chataim and gezeiros that may hang over our nation; if we truly desire Eretz Yisrael, Hashem will provide the opportunity for it to be ours.