And then the mitzvah to be happy will be yet another yoke on our shoulders. Rather, Hakadosh Baruch Hu doesn't command it, and we are happy on our own, happy with receiving the yoke of Torah and happy with the bar mitzvah."
People make a grand celebration by a chasunah, which is the fulfillment of the first mitzvah of the Torah (ורבו פרו), and at a hachnasas sefer Torah, which is the final mitzvah of the Torah (הזאת השירה את לכם כתבו ועתה). The Chidushei HaRim zt'l explains that we should really make a great celebration for each mitzvah we perform, but it would be impossible. Therefore, we make a celebration solely for the first and the final mitzvah of the Torah.
Another pasuk that speaks about our obligation to serve Hashem with joy is (Tehillim 100:2) בשמחה 'ה את עבדו. The Rambam (Hilchos Lulav 8:15) states, "The joy that a person has when he performs a mitzvah, and his love to Hashem Who created him, גדולה עבודה היא, is a great avodah, a great service to Hashem."
Each mitzvah has its segulah, and yet, sometimes, we perform mitzvos but don't see the segulos coming through! Reb Chaim Vital zt'l (Hakdamah l'Shaar HaMitzvos) addresses this problem and explains why. He writes, "We see people performing mitzvos, but we don’t see the words of Chazal, which discuss the reward even in this world, happening. The primary factor for this is that when one does a mitzvah, he shouldn't consider it like a yoke, something that he wants to finish as soon as possible. Instead, he should think that he is earning millions (זהב דנרי אלפים אלף) with every mitzvah he performs. He should be very happy with the mitzvos, and perform them with great desire, as though he is actually earning the millions for each mitzvah he performs."
Similarly, Orchos Tzaddikim (Shaar HaSimchah) writes, "Whoever performs a mitzvah with joy, his reward will be a thousand times more than those who perform the mitzvos as though they are a heavy load."
The Gemara (Shabbos 30:) states that the Shechinah resides solely where there is joy. And the Vilna Gaon zt'l (Oros HaGra, Simchah) writes, "Atzvus is a mum, a blemish, and whoever has a blemish, can't come to kedushah. This is the reason one needed to be happy in order to come to the Beis HaMikdash."
How can one acquire this great joy? A person should think about this tremendous opportunity that he, a human being, can serve Hakadosh Baruch Hu, the King of all kings. The Orchos Tzaddikim (Shaar HaSimchah) writes, "When you perform the mitzvos, be happy in your heart that you have the merit to serve the Divine King, to Whom the malachim bow down."
To better explain the great joy that is required when performing mitzvos, let us look at the Or HaChaim HaKadosh (Shemos 12:3) on the pasuk שה איש להם ויקחו, which is talking about the sheep that the Yidden took for the korban Pesach. In this pasuk, the word איש seems extra. איש represents Hakadosh Baruch Hu, as Chazal (Sotah 42:) tell us ה"הקב אלא איש אין. This was the Yidden’s first mitzvah, and at this time, Hashem wanted to show them what they would attain when they performed the mitzvos. איש ויקחו, it will be like they are taking Hakadosh Baruch Hu because when a Yid performs a mitzvah, Hashem resides on the Yid who performs it. This is also the intention of (Shemos 22:2) תרומה לי ויקחו... The word לי is extra, and the Midrash Tanchuma (3) writes that this means we should take Hakadosh Baruch Hu with the mitzvah. For this is what occurs when we perform the mitzvos. We become connected with Hakadosh Baruch Hu. This is also the intention of the pasuk (Devarim 28:10) נקרא 'ה שם כי הארץ עמי כל וראו עליך, because of the mitzvos, it will be noticed that Hashem resides with Yisrael.
Thinking about these wondrous ideas will undoubtedly fill our hearts with joy when we perform the mitzvos.
