I’ve known rivers ancient as the world and older than the flow of human blood in human veins.

The speaker conveys the idea that Black people have timeless, ancient roots that go back to before the dawn of humankind, especially considering that Africa is widely considered to be the birthplace of humanity. This description also conflates the flow of river with the flow of blood, as though the earth itself were a living, breathing entity much like a human body.

My soul has grown deep like the rivers.

Langston compares the souls of Black Americans to the depths of ancient rivers, such as the Euphrates, the Nile, and the Congo. This analogy conveys the idea that Black Americans have souls that have grown deep over millennia because of traumas and triumphs that have spanned the globe. This line is repeated twice, once near the beginning and again at the poem’s conclusion, which has helped make it both memorable and iconic.

I bathed in the Euphrates when dawns were young.
I built my hut near the Congo and it lulled me to sleep.
I looked upon the Nile and raised the pyramids above it.

With the repetition of the pronoun “I,” the speaker emphasizes how much experience he has gained and how many lives he has lived. This use of the first person is similar to how Walt Whitman uses the first-person “I” in his poems in that it is not limited to a single person’s experience. Rather, it encompasses the lives of all people of African descent. In a sense, these lines present a broad overview of the history of African people. The Euphrates refers to the Fertile Crescent in Mesopotamia, also known as the “cradle of civilization.” The Congo River, located in the heartlands of Africa, is among the longest rivers on the African continent and is also the deepest in terms of water volume. Finally, the Nile River helped the ancient Egyptians become a prosperous and powerful empire. The fact that this empire was largely built by slave labor also serves to mirror the practice of slavery in the United States.

I heard the singing of the Mississippi when Abe Lincoln went down to New Orleans, and I’ve seen its muddy bosom turn all golden in the sunset.

After speaking of Old World rivers like the Euphrates, Nile, and Congo, Hughes writes about a New World river—the Mississippi. This river becomes personified, singing when Abraham Lincoln and emancipation arrive. The Mississippi turns “golden” when the Union wins the Civil War and slavery is abolished, signifying the dawn of a new era. In a sense, the fate of Black Americans becomes connected with this river.