Original: Nusrat Fateh Ali Khan ( , October 13 1948 -- August 16 , 1997 ) , was a legendary Punjabi musician , primarily a singer of Qawwali , the devotional music of the Sufis ( a mystical tradition within Islam ) .
Simplified: He was a singer of qawwali , the devotional music of the Sufis ( a mystical tradition in Islam ) .