电影《塞尔玛》讲述了发生在上世纪60年代，美国民权运动领袖Martin Luther King, Jr.发起的争取黑人权益的游行（Selma to Montgomery March），成千上万人组成的队伍由阿拉巴马州塞尔玛市出发，费时五天四夜，达州首府蒙哥马利市的州会大楼，为争取选举权展开活动。这些活动直接推动了1965年《投票权利法案》的通过，让黑人的选举和被选举权利得到保障。

提到Martin Luther King, Jr.，大家就会想起他的演讲“I Have A Dream”。其实，在塞尔玛游行结束后，他也发表了著名的演讲，命为“How Long, Not Long”，小编摘选两段和大家分享：

They told us we wouldn’t get here. And there were those who said that we would get here only over their dead bodies, but all the world today knows that we are here and we are standing before the forces of power in the state of Alabama saying, “We ain't goin' let nobody turn us around”.

I know you are asking today, “How long will it take?” Somebody’s asking, “How long will prejudice blind the visions of men, darken their understanding, and drive bright-eyed wisdom from her sacred throne?” Somebody’s asking, “When will wounded justice, lying prostrate on the streets of Selma and Birmingham and communities all over the South, be lifted from this dust of shame to reign supreme among the children of men?” Somebody’s asking, “When will the radiant star of hope be plunged against the nocturnal bosom of this lonely night, plucked from weary souls with chains of fear and the manacles of death? How long will justice be crucified, and truth bear it?” I come to say to you this afternoon, however difficult the moment, however frustrating the hour, it will not be long, because “truth crushed to earth will rise again.” How long? Not long, because “no lie can live forever.” How long? Not long, because “you shall reap what you sow.” How long? Not long, because “the arc of the moral universe is long, but it bends toward justice.”

作为《塞尔玛》的主题曲，Glory的歌词也非常贴切反种族歧视的主题。歌词中既列举了“罗莎·帕克斯公交车案”，“弗格森枪击案”等种族歧视事件，也强调了，虽然Martin Luther King, Jr.被无情杀害，但黑人运动终将胜利，和平之光将永恒闪耀。