Who said "Gratitude is the highest form of courtesy to existence."?

This quote is attributed to Rubén Darío.

Gratitude is the highest form of courtesy to existence. - Rubén Darío

"Gratitude is the highest form of courtesy to existence."

Rubén Darío Gratitude

Poet Nicaraguan 1867–1916

"I am my own road"

"I seek the divine in all things"

"The poet is a light and a flame"

"To be a poet is to possess wings"

"Gratitude makes life richer."

"A grateful heart is a happy heart."

"Respect those who came before us."

"Life's greatest treasures are the people we love"