“El remordimiento” [Remorse] is a poem from the 1976 collection “La moneda de hierro” [The Iron Coin], selected lines:

I have committed the worst sin of all
That a man can commit. I have not been
Happy….
…
It never leaves my side, since I began:
This shadow of having been a brooding man.

He cometido el peor de los pecados
Que un hombre puede cometer. No he sido
Feliz….
…
No me abandona. Siempre está a mi lado
La sombra de haber sido un desdichado.