The Meforshim ask what was the sin of the meraglim in spying on Eretz Yisrael to determine the best way to wage war against the nations living there at that time. See Ramban and others for the various answers given to this question. On first glance, we may assume that the reason that there was a problem was because they should have tried to enter Eretz Yisrael without preparation at all, in a way similar to how they just lived the last 40 years in the desert, totally dependent on Hashem. However, it seems from the meforshim that Bnei Yisrael understood that just as they were going to be expected to sow and plant the land in order to sustain themselves, so too they were going to be expected to conquer the land through natural means.
Fitting in with this “natural conquest” was Moshe Rabbeinu’s charge: “Are the people strong or weak, few or numerous…” but one of these charges did not seem fit with the desire to conquer the land: Moshe asked that they determine if the land is a “fertile land or a lean land.” Why was this information required for a natural conquest of the land? For this piece of information, they should have relied on Hashem’s word that it was a land flowing with milk and honey. Determining that this was in fact true would not help the conquest. But if Moshe Rabbeinu said it, he must have understood that this was a proper question as well.
I would like to offer an answer based on the question of Rabbi M. D. Soloveichik. When Klal Yisrael sought to determine if the land was fertile or lean, they showed a lack of trust in whether Hashem was giving them a land flowing with milk and honey. Why then would Moshe repeat this over? It seems to me that when Moshe Rabbeinu heard this request, he assumed that Bnei Yisrael were already convinced that the land was good, and by getting this additional piece of information he could use it as a motivation for the natural conquest of the land: The spies would come back with detailed stories of the glory of the land, which would raise the level of motivation of the soldiers and increase their drive to succeed at war.
Many times, people ask certain questions or give explanations that can be understood at one level as totally legitimate and very much in place. On the other hand, the exact same question can be coming from a place of decadence and defiance in Hashem. We in our own lives sometimes may ask a question with a little of both. We should take the lesson from this parsha to decide if our question is coming from a place of negativity or whether the question is driven by a desire to reach greater heights in our avodas Hashem.