Why were the spies commanded to assess if the Land is good?

Question

God promised that the Land he would bring us into was good. Exodus 3:8:

and I am come down to deliver them out of the hand of the Egyptians, and to bring them up out of that land unto a good land and a large, unto a land flowing with milk and honey; unto the place of the Canaanite, and the Hittite, and the Amorite, and the Perizzite, and the Hivite, and the Jebusite.

Yet despite this assurance, the spies were instructed by Moses to assess whether the Land was good. Numbers 13:17-20:

And Moses sent them to spy out the land of Canaan, and said unto them: 'Get you up here into the South, and go up into the mountains;and see the land, what it is; and the people that dwelleth therein, whether they are strong or weak, whether they are few or many; and what the land is that they dwell in, whether it is good or bad; and what cities they are that they dwell in, whether in camps, or in strongholds; and what the land is, whether it is fat or lean, whether there is wood therein, or not. And be ye of good courage, and bring of the fruit of the land.'--Now the time was the time of the first-ripe grapes.--

Given that God had already promised us a "good land" (large, and flowing with milk and honey), why did Moses require that the spies inspect whether the Land was "good or bad"?

Answer 1

One of the commentaries on this subject is given by the Sforno on Bamidbar 13:18. The Sforno explains that they needed to find out if the ecological conditions, but also the climate in which the people lived favoured successful.

ואת העם היושב עליה, to find out if the ecological conditions favoured successful settlement in cities. In other words, if sick people would be referred by their physicians to such cities and to such a climate to help them regain their health. They would judge this by the appearance of the inhabitants of such cities; if they appeared healthy, strong, of good posture, etc. They would also observe if the people were numerous, had large families, or if somehow they were few in numbers. Large numbers of people, and people looking strong and fit, would indicate that the climate was good and favoured large-scale settlement.

The Or HaChaim explains that when Moshe Rabbeinu instructed the spies to "see the country", they needed to see if the nature of the people, e.g. their health or strenght reflected the land they lived in, e.g. Eretz Yisrael:

וראיתם את הארץ מה היא, "and you will observe the nature of the land." This was a reference to the climate of the land, the topography of the land such as whether it had many natural sources of water, and if such sources of water were pure or contaminated, etc. Moses referred to those aspects of the land which anyone traversing it can determine with ease. When he told the spies to evaluate the people, i.e. ואת העם היושב עליה, he asked them to evaluate if the nature of the people, their health, their strength, etc. reflected that the land they lived on had contributed to these people's being healthy, etc. Moses suggested that the health of its inhabitants was proof of the goodness of the land these people dwelled on. Seeing that it could be argued that if the people were extremely robust this might be due to such factors as healthy living habits, in particular not overindulging in sex, he asked the spies to find out if the people were numerous or relatively few in numbers. If the people were numerous this too would be testimony to the topographical and climatic conditions being favourable.

So, it would seem that the reason the spies were instructed to observe the people and the country, was due to the fact that the Torah mentions Eretz Yisrael as " a good land and a large, unto a land flowing with milk and honey". Since the country was good, the people surely needed to be on that same level, since they lived in it.

Answer 2

Human Validation of [Shemot 3:8] is requested by HaShem (not Moshe) in [Numbers 13:2] | HaShem's request for scouts "to-explore" (לָתוּר) the promised land for the Bnei Yisrael is obediently fulfilled by Moshe in [Bamidbar 13:3] "Moshe sent them" (יִּשְׁלַח אֹתָם משֶׁה) "by-[the]-Mouth of YHVH" (עַל־פִּי יְהֹוָה).

Trusted witnesses כָּלֵב Kalev & הוֹשֵׁעַ Hoshea would confirm to Bnei Yisrael the validity of the promise from the Mal'ak in [Shemot 3:8] to strengthen the credibility of Moshe's claims regarding HaShem.

Sadly without instruction from HaShem, Moshe demonstrates favoritism in [Bamidbar 13:16] by blessing only Hoshea's safety in Canaan (through the title Yehoshua) causing possible bias in 1 testimony of HaShem's 12 scouts.