The Great Mitzvah of Joy by Rabbi Chaim Kramer From Breslov.org
“Serve God with Joy!” (Psalms 100:2).
Rebbe Nachman teaches: It is a great mitzvah to be happy always.
Strengthen yourself to push aside all depression and sadness. Everyone has lots of problems and the nature of man is to be attracted to sadness. To escape these difficulties, constantly bring joy into your life – even if you have to resort to silliness (Likutey Moharan II, 24).
Joy is the hardest of all levels to attain and maintain (Rabbi Nachman’s Wisdom 20). When contemplating our daily pressures and workloads, this is very easy to understand. Happiness is not specified in Torah as a separate mitzvah. Yet, throughout the Talmud, Midrash and Kabbalah, joy is given centrality in all areas of Judaism. The renowned Safed kabbalist, the Ari (Rabbi Yitzchak Luria, 1534-1572), asserted that he attained his exalted spiritual level only because of the great joy with which he performed the mitzvot (Sha’ar HaKavanot, Shemini Atzeret). Indeed, not many of the subjects discussed in Breslov literature receive the detailed attention given to joy and happiness.
Reb Avraham Chazan commented: If Rebbe Nachman taught that it’s a great mitzvah to be happy always, then we must believe that there is what to be happy about! (Rabbi Eliyahu Chaim Rosen).