"Rebbe Nachman of Breslev teaches that music originates from the upper portals of Heaven. He also teaches that one can't attain true joy in life without holiness. Joy is holiness and holiness is joy. In that music has such a lofty source, it has the power of elevating a person to phenominal spiritual heights, especially music played by a joyful and upright musician. Music, joy, and holiness together create an upward spiritual spiral that is capable of uplifting a person from depression and despair, especially when reinforced with extensive personal prayer.
"I often incorporate music into my personal prayers. Oftentimes, when I'm at a loss for words, I sing to Hashem or hum a niggun
, a melody."READ the whole thing here
, which includes two links to videos of Chaim Dovid, including his famous "Ya-ma-mai" niggun