The spies came back with the good fruit from Canaan.
They reported that they fulfilled their mission.
Their mission was Number 13v 18-20
"See what the land is like and whether the people who live there are strong or weak, few or many. What kind of land do they live in?
Is it good or bad?
What kind of towns do they live in?
Are they unwalled or fortified?
How is the soil? Is it fertile or poor?
Are there trees in it or not?
Do your best to bring back some of the fruit of the land." (It was the season for the first ripe grapes.)
Moses asked about the people, agriculture - quality of the land,industry of the towns and its defences. and come home with an example of the produce. They done a pretty good job in executing the executive order it took them 40 days.- but they carried their attitude of pessimism with them.
Previously in Numbers 11:4 "The rabble with them began to crave other food" V10 "Moses heard the people of every family wailing at the entrance to their tents. The LORD became exceedingly angry, and Moses was troubled". The rabble infiltrated the thoughts and attitudes of the whole nation (v21 six hundred thousand men on foot) so that every family was affected. Then we have just read about Aaron and Miriam grumbling against Moses.
The twelve who went out only two had anything positive to say about their abilities. Their attitude disabled their abilities to take the land.
And they spread among the Israelites a bad report about the land they had explored. They said, "The land we explored devours those living in it. All the people we saw there are of great size. 33 We saw the Nephilim there (the descendants of Anak come from the Nephilim). We seemed like grasshoppers in our own eyes, and we looked the same to them."
Exaggeration of perception on their size led to exaggeration of the opposition's also. The Israelites seen themselves as grasshoppers "and we looked the same to them". Apparently they could now read minds! When we get like them and become overwhelmed a renewing of the mind needs to take place not guessing at what is in other people's minds.
40 days exploration led to inaccurate assessment of Gods ability, which led to 40 years of walking in circles and the next generation still having to fight the battle their forefathers should have won.