Likutei Moharan 24:2/ליקוטי מוהר"ן כ״ד:ב׳

12. And know! It is impossible to even grasp [the Light] in the aspect of reaching and not reaching except by performing the mitzvot with joy. This is because through the joy of the mitzvah, holiness is perfected. It elevates the vitality and the holiness that are in the evil forces, similar to the eleven spices of the incense.

2For the evil forces are an aspect of excess, and they correspond to sorrow, as in (Proverbs 14:23), “In all sorrow there is excess.” They are also harsh judgments, corresponding to (Genesis 6:6), “He felt sorrow in His heart….” And the essence of joy is in the heart, as is written (Psalms 4:8), “You have put joy in my heart.”

3Now, the exile of the Divine Presence—which corresponds to the heart, the joy of Israel—is primarily when sorrow, the evil forces, overcome her. This is as in, “He felt sorrow in His heart.” Thus it is written that when the Jewish people will go out of exile (Isaiah 55:12): “For you will go out with joy.”

4And because of this—that through the incense, the vitality of the evil forces are extracted—it is written of them (Proverbs 27:9), “Incense gladdens the heart.” Thus when a person performs a mitzvah with joy, he then elevates the Divine Presence—which is the mitzvah, the joy of the heart—from among the evil forces.

5This is the concept of Malkhut of the World of Action ascending from the evil forces.