During the Montgomery bus boycott "it was black Christians teaching white Christians what it meant to be Christian," says a white Lutheran pastor who joined Martin Luther King Jr. and others in a movement to change the world.

Watch much more of our conversation with Rev. Robert Graetz, who calls the Montgomery bus boycott a spiritual movement based on love and nonviolence that transformed the hearts of people across the country.

Read more of Kim Lawton's interview with Rep. John Lewis about religion and the civil rights movement.