It's not ideas with which we write poetry, it's with words. Literature is first words. When we think about words, we have the tendency to consider them simply as tools for communicating and we forget that authors, like us, can play with words. We forget the two fundamental notions with respect to words (1) that words are not simple tools with one clear and simple sense, but that they have many meanings and (2) that words have two dimensions, the material side (letters, sounds) and the intellectual side (meaning) To learn a language and read its literature, is just learning to play with words, with the meanings of words, with the sounds of words and above all with the associations provoked by words.
(Autour de la litterature)
My translation; please excuse any errors.