Tourists Or Spies 

In describing the mission of the spies, The Torah uses the word "la'tur", which means 'to tour' or 'to scout', rather than the word 'to spy'.  (Num 13:2,17,25) 

"You shall see the land, what it is, are the people strong or weak, few or many?  Is the Land good or bad?  Are the towns open or fortified?  Is the soil rich or poor?  Are there trees and if so, bring back samples of the fruit."   (Num 13:17-20)

The 'spies' had two objectives:

1) To find out about the nature of the land - whether it was good or bad, the soil rich or poor, the trees fruitful. 

2) Concerning the feasibility of conquest - to find out if the enemy was strong or weak, the cities fortified or open.

This 'fact finding' mission was quite different from a 'spy mission'.  The twelve men, one from each tribe, were sent publicly, to gather information for the entire nation, while in a 'spy mission', usually a small group is sent secretly, and reported back to the military commanders, not to the entire nation.

The 'spies' were instructed to scout the land to determine the feasibility of its conquest, and prepare the land for its two million new inhabitants.  Forty years later the Torah recorded: 

"YHVH spoke to Moses:  These are the names of the men through whom the land shall be apportioned - Eleazar the Priest and Joshua the son of Nun.  And one prince from each tribe... each one a chieftain among them... all the men being leaders of Israel, and these are their names."   (Num 34:16-29 and Num 13:1-3)

The 'spies' reported back to Moses and the entire nation. (Num 13:26)  Had they been military spies, they would report only to Moses, their military commander, and there would be no reason to publicize their names. 

Joshua's Spies 

Let us compare these 'spies' with the spies sent by Joshua.  

"And Joshua... secretly sent two spies saying, go scout out the land and the area of Jericho... and the two men returned... and they came to Joshua and they told him concerning what happened to them."   (Josh 2:1, 24)

Here the spies were actually referred to as spies ('meraglim' in Hebrew).  They were sent secretly (no names) to spy out the city and report back only to Joshua.  Their mission was purely military.

Moses sent: 12 men, Tribal leaders, publicly, "to tour" the type of land, its fruit, its cities etc..                          
Joshua sent:  2 men, unnamed, secretly, "to spy", only military information.

Joshua's spies served as military spies, to help him plan how to conquer Jericho.  Moses' 'spies' served as an inquiry commission, to provide the people with information helpful in the establishment of the new nation.

One Report, Two Opinions

When the 'spies' returned, their report correlated perfectly with the dual nature of their mission.

"They returned to Moses and Aaron and the entire nation... and showed them the fruits of the land saying... it is indeed a land flowing with milk and honey.  Alas, for the people who live in that land are mighty, and the cities are fortified... the Amalekites guard the south, the Hittites and Amorites control the mountain range, and the Canaanites command the planes. "  (Num 13:26-29)

In regard to the nature of the land - all the 'spies' conclude that the land was excellent.  In regard to the feasibility of its conquest, the majority's opinion was that it was impossible.  Only Caleb and Joshua had a different opinion.  Based on the same findings, they concluded that conquering the Land was possible.

"It is indeed feasible to conquer the Land."  (Num 13:30)

The majority opinion appeared to be logical and quite realistic.  Why then was YHVH so angered?

It is generally understood that the sin of the spies stemmed from their lack of faith and trust in YHVH.  Had they believed in Him, they would have arrived at the same conclusion as Caleb and Joshua.  However, there was more to it.  

No doubt, the tribal leaders and the entire nation believed in YHVH, but they also remembered  the warnings:

"Behold I am sending an angel to lead you into the Land.  Be careful and listen to his voice, do not rebel against him, for He will not pardon your sins, for My Name is with him.  For if you will listen and do everything that I command you, then I will help you defeat and conquer your enemies."   (Ex 23:20-25)

The 'spies' knew that YHVH's assistance depended on Israel's obedience.  They did not doubt YHVH's ability to assist them, rather they doubted their own ability to fully obey and be worthy of that assistance.

The Sin Of The 'Spies' - Their Evil Report

The leadership should have inspired the people to rise to the challenge.  Instead, they attempted to shape public opinion with excuses. 

"The people who went up with Caleb said, we cannot attack that people for it is stronger that we.  And they spread an evil report among Israel saying, the land which we visited is one that devours its inhabitants, all the people who we saw there are giants... we looked like grasshoppers to ourselves, and that is how they saw us."  (Num 13:30-33)

A land does not 'devour' its inhabitants, nor is it likely that the Canaanites perceived them as 'grasshoppers'.  Rather than confessing their fear, ten of the 'spies' stressed the seriousness of the situation and created fear in the camp.

"And the men that brought up the evil report, died in a plague before YHVH."   (Num 14:37)

Caleb and Joshua, on the other hand, exhibited true leadership with their response. 

"If YHVH truly wants us to be His nation, surely He will bring us into the land... only you must not rebel against YHVH, and you should not fear the people, for they are our prey... for YHVH will be with us.  Do not fear them."    (Num 14:8-9)

Unfortunately, the others were more convincing, and the people concluded that attacking Canaan at this time would be suicidal.  (Num 14:1-4)  Joshua's and Caleb's attempt to convince the people otherwise failed.  Israel preferred returning to Egypt instead of taking the challenge of becoming YHVH's special nation in a special Land.  (Num 14:3-9)

Why not punish the ten 'spies' only for leading the people astray?  Why did YHVH punish the entire nation?

The people's choice to believe the evil report reflected their own spiritual weakness.  Since the time of the Exodus, they consistently showed lack of faith.  This entire incident only strengthened YHVH's earlier conclusion that Israel was not ready to fulfill their calling, hence His decision to give the entire nation more time.  

"YHVH spoke to Moses: How long will this people continue to defy Me, and how long will they have no faith in Me, despite all the signs (miracles) that I performed in their midst...  For all those men saw My Glory and My signs in Egypt and in the desert, and they have tested me ten times, yet they did not listen to My voice.  Surely they will not see the land that I promised to their forefathers.  However My servant Caleb will see the land, for he had a different spirit... and had followed me fully."  (Num 14:11-13, 21-24) 

Israel's punishment was not based solely on the sin of the 'spies', but rather on their overall attitude and behavior since the time they left Egypt.

Moses prayer for Mercy in the aftermath of this event, as he did after the sin of the 'golden calf'.  However, this was more severe and the consequences more devastating.  

When the people finally had a change of heart and were ready to say, "We will go up and conquer the place that YHVH had spoken of, for we were wrong" it was too late. (Num 14:39-45)  Had this been their only sin, most likely their repentance would have sufficed.  However, this 'desert generation' had an 'heart problem' which could not be overlooked any longer, and the remedy - a whole generation will perish slowly in the desert, until a new generation grows up and become properly educated.