In this week’s parshah, we learn about the sin of the spies, who spoke against Eretz Yisrael and dissuaded Bnei Yisrael from entering. Hashem threatened to immediately destroy the entire nation in punishment, but Moshe Rabbeinu prayed on their behalf, awakening Hashem’s mercy:
ויאמר משה אל ה' ושמעו מצרים כי העלית בכחך את העם הזה מקרבו. ואמרו אל יושב הארץ הזאת שמעו כי אתה ה' בקרב העם הזה אשר עין בעין נראה אתה ה' ועננך עמד עלהם ובעמד ענן אתה הלך לפניהם יומם ובעמוד אש לילה. והמתה את העם הזה כאיש אחד ואמרו הגוים אשר שמעו את שמעך לאמר. מבלתי יכלת ה' להביא את העם הזה אל הארץ אשר נשבע להם וישחטם במדבר. ועתה יגדל נא כח ה' כאשר דברת לאמר. ה' ארך אפים ורב חסד נשא עון ופשע ונקה לא ינקה פקד עון אבות על בנים על שלשים ועל רבעים. סלח נא לעון העם הזה כגדל חסדך וכאשר נשאתה לעם הזה ממצרים ועד הנה.
ויאמר ה' סלחתי כדברך. ואולם חי אני וימלא כבוד ה' את כל הארץ. כי כל האנשים הראים את כבדי ואת אתתי אשר עשיתי במצרים ובמדבר וינסו אתי זה עשר פעמים ולא שמעו בקולי. אם יראו את הארץ אשר נשבעתי לאבתם וכל מנאצי לא יראוה.
And Moshe said to Hashem, “Then Egypt, from whose midst You brought this nation out with Your strength, will hear, and they will say about the inhabitants of this land, ‘They have heard that You, Hashem, are in the midst of this nation – that You, Hashem, appeared eye to eye and Your cloud hovers over them, and that in a pillar of cloud You walk before them by day, and in a pillar of fire by night – yet You killed this nation like a single man!’ Then the nations who have heard Your renown will say, ‘Because Hashem was unable to bring this nation into the Land He had sworn to them, He slaughtered them in the desert.’
“So now, let the power of my Lord be exalted, as You have spoken, saying: ‘Hashem, patient, great in kindness, bearer of iniquity and willful sin, and who cleanses [some] but does not cleanse [others], visiting the sins of parents upon children to the third and fourth generations.’ Please forgive the sin of this nation, as befits Your great kindness, and as You have borne this nation from Egypt until now.”
And Hashem said, “I have forgiven, as you have spoken. However, as I live, I swear, that the Glory of Hashem shall fill the entire world, and all the men who have been shown My Glory and the wonders I performed in Egypt and in the desert, and who have tested Me these ten times and defied My voice, if they will see the Land that I have sworn to their forefathers! All those who have angered Me shall not see it.”
Rashi explains Hashem’s vow that “His Glory shall fill the entire world” as a consent to Moshe’s claim that if He were to kill Bnei Yisroel at once, “like a single man,” it would seem as though He were incapable of bringing them into Eretz Yisroel and defeating the warrior kings of Canaan. Although Bnei Yisroel were deserving of destruction and Moshe’s invocation of Hashem’s Thirteen Attributes of Mercy was insufficient to protect them, Hashem nonetheless spared them so as not to diminish His Glory in the world.
Another explanation of this vow can be suggested based on Rashi’s interpretation of the possuk:
המה מי מריבה אשר רבו בני ישראל את ה' ויקדש בם.
These are the waters of controversy, where Bnei Yisroel contended with Hashem, and He was sanctified through them.
Rashi explains that Moshe and Aharon died as a result of this controversy, since in striking the stone rather than speaking to it they failed to precisely heed Hashem’s instructions. When those closest to Hashem are punished for their sins, His Name is sanctified, since people realize that there is no protectionism. Even the greatest, holiest people in the world are held accountable for their sins. Here, too, although the spies were distinguished individuals, the very leaders of their Tribes, they were still severely punished and forced to die gruesome deaths in the desert. This was a sanctification of Hashem’s Name through which His Glory would fill the entire world.
A third explanation can be suggested based on the Netziv’s commentary, Ha’Emek Dvar, in which he cites sources in Tanach where we find that our exile from our land is a punishment for the sin of the spies. David states in Tehillim:
וימאסו בארץ חמדה לא האמינו לדברו. וירגנו באהליהם לא שמעו בקול ה'. וישא ידו להם להפיל אותם במדבר. ולהפיל זרעם בגוים ולזרותם בארצות.
They despised the Desired Land and did not believe His word. They complained in their tents and did not heed the voice of Hashem. He raised His hand [to swear] that He would strike them down in the desert, strike down their descendants among the nations, and scatter them among [foreign] lands.
And the Sefer Yechezkel similarly relates:
נשאתי את ידי להם במדבר להפיץ אתם בגוים ולזרות אותם בארצות.
I raised My hand [to swear] against them in the desert, that I would diffuse them among the nations and scatter them in [foreign] lands.
Accordingly, our Sages tell us that the destruction of the Beis HaMikdash and the exile of Bnei Yisroel from our land was a result of our unwarranted cries on that ominous night of Tisha B'Av. Since we wept baseless tears that night, Hashem established it as a night of crying throughout the generations. Yet nowhere in our parshah is there a explicit reference to this, the most severe punishment of all.
In explanation, it seems that the reference to this punishment is none other than Hashem’s vow “that the Glory of Hashem shall fill the entire world.”
There are two ways by which Hashem’s Name can be sanctified and His Glory revealed. The first, as Hashem had originally intended, would have been through Bnei Yisroel’s entry into Eretz Yisroel with firm faith in His limitless power to guide them on a spiritual path transcendent of nature. Then, the entire process of Bnei Yisroel’s conquering and settling Eretz Yisroel would have been overtly miraculous. Hashem’s Name would have been sanctified throughout the world as a result of the miracles He would have performed for His beloved children. The nations would then have had no choice but to recognize that “Hashem, the G‑d of Israel, is the King; and His kingship extends over all the realms.”
However, this was not to be. The spies planted seeds of doubt in our hearts. They rendered us unable to cleave to Hashem with faith and trust. They intimated that our conquest of Eretz Yisroel would depend on our own physical might, which was insufficient before the mighty warrior kings of Canaan.
Since we accepted their venomous words, we proved ourselves unworthy of the first way of revealing Hashem’s Glory. The alternative method then became necessary. Rather than bringing Glory to Hashem’s Name through the miracles of our peace and prosperity in our homeland, we would need to glorify His Name through the equally astounding miracles of our survival in the dark chasm of exile. Rav Yaakov Emden, zt”l, writes:
When we contemplate our situation in the history of the world, we realize that we are a nation exiled like scattered sheep. After all the thousands of years of hardship that have befallen us, there is no nation as oppressed as ours. Our enemies are numerous. With hatred and jealousy, they have raised their heads to uproot and destroy us. Even so, they have been unable to fulfill their plans. The most powerful of nations have risen against us and long ago fallen, their memory forgotten like a passing shadow, but we who cling to Hashem survive today. Despite all the torments of our exile, we have not lost from our belief even one letter of the written Torah, and the words of our Sages still stand strong. They have been impervious to the hand of time. What could the clever philosophers possibly say to explain this? That it is a coincidence?
By my life, I swear that this is greater in my eyes than the miracles that Hashem performed for our forefathers in Egypt, in the desert and in Eretz Yisroel. The longer the Golus lasts, the more the miracle becomes obvious, and Hashem’s might is revealed. Everything that we undergo today was already foreseen by the prophets, who bemoaned the terrible length of the Golus long before it began. From all their words, not one has fallen aside. He who would dispute this, his words are like smoke and the passing clouds.
Hashem swore to scatter us among the nations in punishment, since this was the only path remaining by which His Glory could be revealed throughout the world.
When Hashem first fashioned the world, He made its existence conditional upon Bnei Yisroel’s reception of the Torah; if they would accept it, the world could survive, but if they would refuse it, the world would revert to tohu u’vohu. Some explain tohu u’vohu to mean “astounding nothingness.” The Ramban, however, explains that these are the most basic, elemental building blocks which Hashem first created in order to construct His world. What, then, was the meaning of the warning that the world would revert to tohu u’vohu? If Hashem found that His world did not achieve its purpose, He could destroy it entirely. Why revert it to the rudimentary building blocks of tohu u’vohu?
According to what we have explained, we can interpret this to mean that the ultimate purpose of Creation was that Hashem’s Glory would be revealed on every plane of existence. Ideally, this could be achieved by Bnei Yisroel accepting and fulfilling the Torah and thereby imbuing all levels of Creation with immeasurable holiness. However, if they would refuse to do so, the world would have to be taken apart and rebuilt, “rebooted,” as it were. A new way would have to be found by which Hashem’s Glory could be revealed, since this is the ultimate, inevitable purpose of Creation.
 Bamidbar 14:13-23
 Bamidbar 20:13
 Tehillim 106:24-27
 Yechezkel 20:23
 Taanis 29a
 Introduction to his commentary on the siddur.
 Shabbos 88a
 See Rashi