That's beautiful. Now that I know the meaning, it will serve as a reminder for me everytime I see it. Serving God with Joy is something I'd like to be better at, sometimes I serve from obligation and I think God would be more pleased with joy.
Here is a rabbi's interpretation of this
A hallmark of Jewish philosophy, particularly within the Chabad and other Chasidic movements, places a great emphasis upon a joyful service of G-d. When one considers the long and difficult history of the Jewish people, one may ask in all fairness, "Why and how does one do this?"
Serving G-d with a joyful attitude is a Mitzvah, as the daily prayers say,
"Ivdu et Hashem bi'simcha"
(Serve G-d with joy)! Is it realistic to demand a joyful service of our Creator in light of all the difficulties found within the world, and most notably those that have faced and continue to face our nation?
The Baal Shem Tov, originator of Chasidic Philosophy, emphasized the need for this critical mindset, as he developed his approach to divine service nearly 300 years ago. His prayers were conducted in a state of near ecstasy, and such has been the custom of Chasidim since his times.
This euphoric state is reached not by ignoring what is occurring in the world around us, but instead because of what we see. The first fact that should bring any of us to great happiness is the fact that the Master of the Universe has entrusted us with His most precious gift, the Torah. It is the greatest honor to have been chosen as keepers of G-d's will and wisdom that are espoused within the Torah. Every commandment that we fulfill draws us closer into the bosom of our Creator. It is His ultimate expression of love for us, that He has given us His Torah that lends meaning and value to our lives. The Torah ennobles our existence!
When we couple this fact with the idea that we Jews believe in a personal G-d, a G-d that takes a "personal interest" in how we live our lives, and therefore is intimately involved with every aspect of our lives, we come to an increased state of joy.
It is true that there is much darkness in the world, but at least we have been given a method to dispel the darkness using the light of Torah. There is always hope. Hope creates joy and gives purpose to those who have it. Those people who feel no hope suffer from depression. We know however, that we have a G-dly soul, described as a "Veritable portion of G-d Above!" How can one with such a powerful force within, not feel happiness?