In his speech, President Roosevelt is asking his audience to unite and take action to address the economic challenges facing the nation during the Great Depression. He emphasizes the need for cooperation and collective effort by stating, "This nation asks for action, and action now." Additionally, he instills a sense of urgency by declaring, "The only thing we have to fear is fear itself." These rhetorical devices convey his call for unity, courage, and decisive action in facing the economic crisis.