If you've never heard of Fannie Lou Hamer, I recommend reading This Little Light of Mine. From Wikipedia:
On August 31, she traveled on a rented bus with other attendees of Bevel's sermon to Indianola, Mississippi to register. In what would become a signature trait of Hamer's activist career, she began singing Christian hymns, such as "Go Tell It on the Mountain" and "This Little Light of Mine," to the group in order to bolster their resolve. The hymns also reflected Hamer's belief that the civil rights struggle was a deeply spiritual one.I think anyone's resolve could be bolstered with Tracie Thoms singing.