"הקרב את מטה לוי והעמדת אתו לפני אהרן הכהן ושרתו אתו. ושמרו את משמרתו ואת משמרת כל העדה לפני אהל מועד לעבד את עבדת המשכן."
“Bring near the Tribe of Levi, and place them before Aharon the Kohen, and they shall serve him. And they shall guard his charge, and the charge of the entire congregation, before the Ohel Moed, to perform the service of the Mishkan.”
In this week’s parshah, we learn of the special tasks imposed upon Tribe of Levi, “the Legion of the King,” as Rashi calls them. The Gemara tells us that the Leviim were divided into two categories: the Singers and the Gate-Keepers. Each duty was so important, and so uniquely tailored for the individual Levi, that our Sages go so far as to say that a gate-keeper who sang, or a singer who kept watch, was liable for death.
It seems that these two duties represent the two-fold nature of our own service of Hashem, in our observance of Torah and mitzvos. The Leviim guarded the Mishkan and Beis HaMikdash, not for fear of attack, but rather as a display of honor, as the Rambam writes:
שמירת המקדש מצות עשה, ואף על פי שאין שם פחד מאויבים ולא מלסטים, שאין שמירתו אלא כבוד לו, אינו דומה פלטרין שיש עליו שומרין לפלטרין שאין עליו שומרין.
There is a positive commandment to guard the Beis HaMikdash, although there was no fear of enemies or thieves. Rather, it was guarded only as a display of honor. A palace around which guards are stationed, cannot be compared to a palace that lies unguarded.
So too, when we guard Hashem’s Torah, and faithfully observe His commandments, we show honor to the Torah, and to He Who granted it. For this reason, we are warned many times never to perform mitzvos in a way that is disgraceful to them. For example, when performing the mitzva of kisui hadam (covering the blood of a slaughtered bird or deer), we must not kick the dirt with our feet, but rather respectfully move the dirt with our hands. We may not count money by the light of Chanukah candles. Similarly, we must show the utmost respect to our shuls, yeshivos, and holy places, since they are our “Mikdash Mi’at” – the microcosm of the Beis HaMikdash, in which the holiness that once dwelt therein accompanies us throughout our sojourn in Golus.
The second aspect of the Leviim’s service, from which we all must learn, is the joy and exhilaration they expressed, as they sang to Hashem with all their hearts, thereby inspiring all who entered the Mishkan. Joy is a crucial element of our service of Hashem, without which all our mitzvos are lacking. The Rambam writes:
השמחה שישמח אדם בעשיית המצוה ובאהבת האל שצוה בהן, עבודה גדולה היא, וכל המונע עצמו משמחה זו ראוי להפרע ממנו שנאמר "תחת אשר לא עבדת את ה' אלהיך בשמחה ובטוב לבב" ... ואין הגדולה והכבוד אלא לשמוח לפני ה' שנאמר "והמלך דוד מפזז ומכרכר לפני ה'."
The joy that a person experiences in the fulfillment of a mitzva, and in the love of Hashem Who commanded it, is a great service. Anyone who refrains from this joy is deserving of punishment, as the possuk states, “Since you did not serve Hashem your G‑d with joy and good heart” … There is no greatness nor honor, other than to rejoice before Hashem, as it is written, “And King David danced exuberantly before Hashem.”
The Rambam notes the terrible retribution the Torah describes, as punishment for failing to serve Hashem with joy. The Ramban writes that this possuk is in fact a reference to the destruction of the two Batei HaMikdash.  Why is the failure to serve Hashem with joy so terrible, that such a devastating punishment results? Furthermore, does this not contradict what our Sages write elsewhere, that the Beis HaMikdash was destroyed as a result of murder, idolatry and illicit relations, or yet elsewhere, where they write that it was destroyed for failing to recite the berachos over Torah study? Nowhere do we find in the Gemara a specific reference to the destruction of the Beis HaMikdash as a result of our having failed to serve Hashem with joy – nor is joy listed among the 613 mitzvos. What then is the great importance of joy in the observance of Torah and mitzvos?
In the beracha recited over Torah study, we say:
והערב נא ה' אלקינו את דברי תורתך בפינו ובפיות עמך בית ישראל. ונהיה אנחנו וצאצאינו וצאצאי צאצאינו וצאצאי עמך בית ישראל כלנו יודעי שמך ולומדי תורתך לשמה.
Please, Hashem our G‑d, let the words of Your Torah be sweet in our mouths, and in the mouths of the entire House of Israel. May we, and our children, and their children after them, and the children of Your nation, the House of Israel, all know Your Name and study Your Torah for its own sake.
This prayer seems to contain two distinct requests. Firstly, we ask that the Torah be sweet and enjoyable to us. Secondly, we ask for the merit to pass on the Torah as an inheritance to the generations that follow, such that our own children, and Jewish children everywhere, may know Hashem, and learn His holy Torah. Why are these seemingly different requests juxtaposed?
In truth, the two requests are very much intertwined. Only when the Torah is sweet to our lips, and our children see how pleasurable and meaningful it is to us, will they be inspired to follow in our footsteps, and seek out the pleasure of Torah on their own.
We can therefore understand how failure to develop the joy of Torah was indeed the indirect cause of the Beis HaMikdash’s destruction. Unable to experience the joy of Torah, our forefathers abandoned the living waters of Torah, to seek out “broken cisterns” of fleeting, meaningless pleasure; and strayed onto wayward paths of foreign ideology – to fill the void that was left, when the joy of Torah was gone. This terrible danger still exists today, when a child is not exposed to the joy of Torah in his home.
The possuk states:
ושמרו בני ישראל את השבת לעשות את השבת לדרתם ברית עולם.
And Bnei Yisroel will guard the Shabbos, to do the Shabbos for their generations, as an eternal covenant.
The term “guard” (ושמרו) refers to prohibitions, while the term “to do” (לעשות) refers to positive commandments. By beginning this possuk with the word ושמרו, the Torah addresses the prohibitions of Shabbos – the 39 melachos, and their derivative tolados. Why then does the possuk also use the term לעשות? The Ramban writes that the prohibitions of the Torah are expressions of our awe and fear of Hashem, while the positive commandments are expressions of our love for Him.
Here, the possuk warns us that if a parent focuses only on the prohibitions of Shabbos, raising his children in an environment of tension and fear, lest they inadvertently violate a law of Shabbos – it is unlikely that they will want to observe Shabbos when they mature. Rather, a person must invest his Shabbos with a positive feeling of “to do”, with the love and joy that accompany the positive commandments. Then he can hope that his Shabbos, and the entire legacy of Torah and mitzvos, will be an eternal covenant for all generations to come.
 Bamidbar 3:6,7
 Bamidbar 1:49
 Erchin 11b; Rambam: Hilchos Klei HaMikdash 3:11. See Minchas Asher, Bamidbar 2
 Hilchos Beis HaBechirah 8:1
 Vayikra 17:13 , Shabbos 22a
 Shabbos, ibid
 Megillah 29a
 Hilchos Lulav 8:15
 Vayikra 26:16
 Yoma 9
 Nedarim 81
 Shemos 31:16
 Parshas Yisro