"Gospel music. Gospel music is a very good example of what I've been saying. It comes from the Negro spirituals African-American slaves used to sing while working in the cotton fields." He swiftly changed the tune to a slower pace, starting the notes of "Swing Low, Sweet Chariot." "In their songs, African-American slaves expressed their suffering and hope for a future deliverance." He changed the tune again and wore a sullen expression starting Nina Simone's version of "My Man's Gone Now." "Blues," he said. "Whether about heartache or general good ole spleen, blues always expresses sorrow or suffering."