The graduate thesis presents Heidegger's understanding of the essence of language, as well as the relation between thinking and poetizing. The thesis relies primarily on the works of Heidegger’s later philosophy, called the thinking of the history of Being. First, the thesis considers the ways in which Heidegger perceives language as Saying (die Sage), and genuine saying as letting and permitting the spoken to show itself. According to Heidegger, man is not really a master of language nor someone who uses it by his own free will; rather, language is the one that rules the man: language speaks, and man has to listen to language if he is truly to speak, with language being first and foremost the language of Being itself. Then, the thesis examines Heidegger’s reflections on Western metaphysics and its limitations, as well as how genuine saying, be it thinking and poetizing, manages to overcome it. In addition, Heidegger's conceptions of the essence of poetry are presented as being in clear contrast to the standard, established opinions about poetry, with both the closeness and the difference of thinking and poetry considered. Furthermore, the thesis identifies the places in Western history where Heidegger recognizes authentic thinking and poetizing: these are on the one side ancient Greek poets and thinkers, and on the other Hölderlin and Nietzsche at the end of Western metaphysics. Finally, some of the ways are mentioned in which with his own style of thinking and saying Heidegger himself comes close to poetizing: writing in forms such as poems, dialogues and fragments, as well as abandoning the traditional rules of grammar and language structures.