The Book and Parsha of Rebuke
The first parsha of the fifth book of the Torah, Devarim, contains Moses’ final words of rebuke and inspiration to the first generation to enter Eretz Yisrael.
Rashi explains that in the opening verse of this book and parsha Moses starts with subtle rebukes, hinting at the many instances in which the Jewish people angered G‑d, such as the sin of the Golden Calf, the rebellious spies and Korach’s rebellion, among others. Moses only alluded to these sins, Rashi explains, to protect the honor of the Jewish people.
“Taking Off His Gloves”
If this is so, commentators ask, why did Moses subsequently “take off his gloves” and reprimand them openly? Indeed, the bulk of this parsha deals with Moses’ rebuke concerning the spies’ debacle in much detail. A contemporary Chassidic author, Rabbi Gershon Mordechai Shpalter, in his Imrei Mordechai, provides an interesting answer to this question.  He points to the famous Chassidic Master, Rabbi Levi Yitzchak of Berditchev and his unequivocal ban on guest rabbis delivering words of rebuke to his congregation.  Rabbi Levi Yitzchak explained that when we rebuke the Jewish community we run the risk of arousing indictments and retribution from the Heavenly Tribunal, G‑d forbid.
Rabbi Shpalter asks, how then can we fulfill the Biblical commandment to rebuke one who has transgressed so that he or she will repent? His answer is to follow Moses’ example: at first, rebuke your fellow gently and subtly.  Most people will get the hint and be moved to change. Once that occurs, there is no longer any fear for heavenly retribution.  Once shielded from heavenly prosecution, Moses felt he could then be more blunt and specific about their indiscretions so that they can do a more comprehensive and profound Teshuvah (repentance or return).
One may add the following to Rabbi Shpalter’s thesis:
To rebuke a fellow Jew one must also follow the example of Moses who was the ultimate lover of Israel. This is why he chose to rebuke them first subtly and gently to show them how much he honored and loved them. Knowing how much he loved, cared and was sensitive to them, the Jewish people were now receptive to hear and internalize Moses’ subsequent direct reproach.
Moreover, had Moses refrained from reprimanding them, he would have been remiss not only in his responsibility as a leader but also as a lover of his people.
This approach can serve as a rejoinder to the modern day swinging pendulum syndrome affecting the way we deal with the flaws of our youth and all those over whom we have influence.
One extreme approach that was common in the past was to unleash all of one’s indignation and fury against those whose behavior fell short of the mark. This approach is both futile and harmful. Its targets react with an even greater determination to continue in their recalcitrant ways. Society, without the guidance of Torah, then swung back in the opposite direction and a spirit of “tolerance” and permissiveness prevailed. Here too we saw disastrous results. Our youths saw parents and teachers, by the sin of omission, advocate a sense that everything goes.  They took that as a license to be each his own final arbiter in determining which direction to go.
The Torah’s approach, as highlighted by Moses’ two-step approach, was to first make the child, in Chassidic jargon, a “vessel” i.e., one who is able to receive and hold on to the message even when it is ultimately delivered honestly and clearly.  How does one create this vessel? It is by following in Moses’ footsteps and showering the recipient of his reprimand with love and demonstrating sensitivity to him or her. 
Why Only the Spy Incident?
The above analysis, however, opens the door for us to ask another question on Moses’ soliloquy in this week’s parsha:
The premise is that Moses first hinted at their transgressions and then, only when they were ready, spelled it all out for them in vivid detail.  Why then does he only speak of the sin of the spies? When Moses begins his message to them, he alludes to all of their sins, from complaining about the Manna to the disgraceful relapse of the Golden Calf and everything in between. Yet, when he feels that they are finally ready to hear all the details, he limits his remarks to the sin of the spies. Why did he omit all the other sins, particularly the Golden Calf, which, according to the Talmud, was Israel’s most heinous crime?
A simple answer to this question is that Moses was addressing the people who were going to enter the Land of Israel. It was important for them to understand the terrible consequences suffered by those who fail to appreciate the central role Eretz Yisrael plays in Judaism. Having grown up in the desert, they might have looked at the conquest and settlement of Israel as just another adventure.  They might have even thought of Israel only as a land where the Jewish people would be safe and secure and that would stimulate a nationalistic pride.
Moses’ message to them was that, first and foremost, the Land of Israel is much more than a homeland. G-s did not give us Israel so we can be equal to all the other nations with a land to call their own.  Our need for Israel transcends well beyond having a place to provide security for the Jewish nation. It is the Holy Land. It is land that “G‑d’s eyes watch over constantly from the beginning of the year to the end of the year.” It is the place that houses the Bais Hamikdash where G‑d’s presence is felt, and the location from which G‑dly inspiration goes forth to the entire world.
I Command You to be Independent!
A deeper answer can be offered when we carefully examine Moses’ acceptance of the idea of sending spies to scout the Land. When Moses asked G‑d whether it was a good idea, G‑d gave neither His approval nor His disapproval.  He essentially told Moses, “You’re on your own.” In light of G‑d’s reluctance to authorize this mission why did Moses give in to the requests of the Jewish people to send these spies?
The Rebbe explains that while G‑d did not instruct Moses to send the spies, G‑d did instruct him to make the decision on his own. While G‑d said, “I am not commanding you to send them,” He was saying, in effect, “I am commanding you to make the decision on your own!”
There is a certain point in time when G‑d says to each and every one of us, “I have given you sufficient commandments and instruction which teach you to how to live your life. I have given you the knowledge and inspiration to endow you with the wherewithal to make the right choices. I have fully empowered you to make the right decisions. You are now on your own. Make the right decisions!” And although G‑d knew the pitfalls of giving people independence—they can make wrong choices, as happened with the spies—it is the only way we can truly grow. Moreover, it is the only way we can fulfill our mission to make the world a G‑dly world without Him imposing Himself on it. By making the choices on our own, the world, of its own volition, “invites” G‑d to enter into it.
Moses therefore singles out this particular episode because he was addressing the new generation in whom G‑d placed the greatest trust. They were no longer going to be guided by a Divine cloud and Pillar of Fire. Miracles that were so common in the desert would be sporadic in the Land of Israel. People would make their own choices without benefit of all of the “external” support systems. It was therefore crucial for Moses to give them the background to this new challenge. He does so by telling them that it was on his own initiative that he sent the spies. Moses acceded to the demands of the people. And it illustrated that this spirit of independence that G‑d welcomes can, and did, result in disaster.
Moses wanted the people to know the immense responsibility that was being settled onto the shoulders of their generation. On the one hand, they were going to be trusted with the mission of conquering the Land in both literal and figurative senses. Everything was being placed in their hands. On the other hand, they had to grasp that they also had an increased capacity to make bad choices, which would undermine their entire mission. There was thus no better narrative than the story of the spies to drive home both of these lessons.
History Repeats Itself
In many ways we are the reincarnation of that generation. We have been told by the Rebbe repeatedly that we are the generation that will enter into the Land of Israel with Moshiach, when he ushers in the Final Redemption. 
In one of his historic talks, the Rebbe said that he was transferring responsibility for bringing on the Redemption to us and that we must do so through our own efforts. We share the same paradoxical relationship with our Rebbe as the Jews in the desert had with Moses. On the one hand, we have been given more guidance and inspiration than any other generation. We have a treasure trove of tens of thousands of letters the Rebbe penned addressing every imaginable problem and challenge. We have hundreds of volumes of the Rebbe’s profound and inspiring teachings. Yet, with our inability now to see and hear the Rebbe, particularly after the Rebbe delegated to us the mission to bring Moshiach, we have been entrusted with arguably the greatest challenge in history.    
The Rebbe also taught us that the greater the challenge, the more power we are given to meet it. Our generation thus has the distinction of being the most spiritually rich generation and entrusted with the formidable task of bringing about the Final Redemption.