"Because you did not serve HaShem, your G-d, with happiness...." (Devarim 28:47). As long as a person fulfills the Mitzvot, what difference does it make whether he serves HaShem with happiness or not? Imagine someone who owns a beautiful house and takes on a project to build a second home. Since nothing compels him to make the house, he will put his plan on the "back burner." Conversely, someone who is without a home will put his full energy into completing the project as soon as possible. Likewise, if a person does not reflect on the supreme delight that HaShem grants him for each Mitzvah that he performs, his Divine service will be "lukewarm." Whereas, a person who is aware of the incomparable reward of each Mitzvah pursues his Mitzvot with great happiness, strength, and dedication.
The first step to serve HaShem is reflecting on the countless blessings, beauty, and pleasantness that we acquire with each Mitzvah, both in this world, as well as, the eternal World to Come.
(1) Envision the sublime joy that filled King David's heart and soul with each Mitzvah that he performed. (2) Transpose King David's pleasure of serving HaShem to your heart and soul. (3) Visualize that the light of Gan Eden shines upon you with each Mitzvah that you perform. (4) Perform your Mitzvot with happiness, vibrancy, and passion. (5) Reap supreme blessings, benefits, and reward both here in this world as well as your eternal life in Gan Eden.
(Based on the commentary of Rav Simcha Zissel Ziv, The Saba M'Kelm)
