This story is part of American Anthem, a yearlong series on songs that rouse, unite, celebrate and call to action. Find more at NPR.org/Anthem.
Ask Freedom Singer Rutha Mae Harris, and she'll tell you plainly: You can't just sing "This Little Light of Mine." You gotta shout it:
"Everywhere I go, Lord, I'm gonna let it shine
Let it shine, let it shine, let it shine!"