Hello. You did not show the text to which this question is related, which makes it impossible for it to be answered. However, I will try to help you in the best possible way.
To answer that question, you must first read the entire excerpt to which the question relates and recognize the subject that Obama is referring to in that excerpt. By recognizing the subject, you will be able to find out whether the underlining phrase is being used to justify Obama's argument, or whether it is intended to motivate listeners about something.
In addition, the sentence may be advising listeners or exposing something or someone. You will be able to recognize this by paying attention to the words used and recognizing how that phrase fits the subject discussed in the excerpt.