In our culture, we imbibe a positivistic understanding of language. That is, we believe that the function of language is only to report and describe what already exists. The usefulness of such language is obvious. It lets us be precise and unambiguous. It even lets us control. But it is one-dimensional language that must necessarily be without passion and without eloquence and indeed without boldness. It is useful language, but it is not the language we have in the Psalms. Indeed, it is not the language in which we can faithfully pray. Such language is useful for managing things. But it makes no impact on how things really are, for things would be the same even if there were no such speech.
By contrast, in the Psalms the use of language does not describe what is. It evokes into being what does not exist until it has been spoken. This kind of speech resists discipline, shuns precision, delights in ambiguity, is profoundly creative, and is itself an exercise in freedom. In using speech in this way, we are in fact doing in a derivative way what God has done in the creation narratives of Genesis. We are calling into being that which does not yet exist.
Walter Brueggemann Praying the Psalms