"How I Got Over" makes a personal religious journey into an allegory for the struggles of Black Americans in the civil rights struggle.
Remember that in a simile, one object is compared to another using a phrase such as "like" or "as" (as in, "life is like a box of chocolates")? And that in a metaphor, an image or concept is used to describe something more directly, usually equating one object or concept with the other (as in the the saying "time is money;" money and time aren't actually the same thing, but you learn something from the comparison)?
In the case of "How I Got Over," the comparison with the Civil Rights Movement doesn't take the form of metaphor or simile, but of allegory. Allegory is a slightly more complicated idea: It makes use of symbols to represent an idea or concept, but doesn't necessarily compare or equate the two ideas or concepts. Often, when you're reading an allegorical story or poem, you have to figure out on your own what the characters and events are supposed to represent.
Much of the song is spent musing about how the narrator made it through her own troubles:
How I made it over Lord, I had to cry in the midnight hour
Coming on over, but you know my soul look back and wonder
How did I make it over?
The lyrics suggest almost unspeakable difficulty, but they're never specific about just what plagued this person's past. In any case, it was Jesus who brought the narrator over to the other side. On the other side, the narrator is "gonna wear a diamond garment" and "view the host in white." At the end, the narrator talks about an angel coming to see her, and thanks God for his gifts.
At this point, you should either be saying, "Ah, yes, I see how that's an allegory for the Civil Rights Movement," or (and this is maybe the more likely option) saying, "Um, I really don't see how this is an allegory for civil rights." We're going to propose an interpretation, but that doesn't mean it's the only possible way to understand the song.
It really could be a song about religious revelation and prayer, and in some senses, it really is a song about just that. The beauty of allegory is that an allegorical story can talk about two or three topics simultaneously. Here, we're thinking that the personal troubles she alludes to symbolize the political struggles of the entire African-American community. The hopes about a diamond garment and a magical, hopeful "other side" refer to the ideals of the Civil Rights Movement: One day, we'll all live in a world of equality and justice, the world of Martin Luther King Jr.'s famous dream. And the act of thanking God for a visit from an angel, after which the singer says, "I 'rose this morning, I feel like shouting" seems to be about the ability of God to inspire the struggle for justice. With God's help, the song says, we can stand up to oppression—and we can survive our personal hardships, too.
This sort of message is quite evangelical, and evangelism is definitely not for everyone. But this song is among many "political" gospel songs that demonstrate how music, poetry and literature can serve several purposes at once. This could be a church hymn or a protest anthem, and over the years it has undoubtedly served as both.