Music, the Avodah of the Leviim

On the pasuk "Kechu mizimras ho'oretz," the Modzitzer Rebbe cites the Kedushas Levi on the words "the songs of your servant Dovid," from Boruch She'omar before Pesukei Dezimra. Music, the Kedushas Levi teaches, is itself a form of avodah, and it was the avodah of the Leviim, who sang and played. Musical scales are called octaves, and they have levels, one above the other. Just as our love and fear of Hashem have levels and scales, so do niggunim. This, the Rebbe explains, is the meaning of "the songs of your servant Dovid."