“Commentary” is a poem that begins by describing the idea that all rivers lead to the sea.

You are looking for the poem “Commentary”.  In Spanish, the name is “Glosa.”  It begins by quoting this idea from Elena Garro.  Translated into English, it reads:

“Our lives are rivers

and rivers flow and move to the sea,

which is our dying.” Marvelous lines! (p. 41)

In English or in Spanish, this is indeed a beautiful idea.  It is based on the Bible.  Essentially, all of our lives are leading to the same place.  We can divide up and spread out, but in the end we all die.  We all come to the same place.  Therefore, we should recognize and take advantage of this fact.

Machado, Antonio, and Robert Bly. Times Alone: Selected Poems of Antonio Machado. Middletown, CT: Wesleyan UP, 1983. Print.