Rhetorical device

Hey
This is a long shot, but I thought I might as well ask.
So I am doing a rhetorical analysis of Barack Obama's acceptance speech at the Democratic National Convention.The thing is, Obama is excellent in repeating words through out his speech as in this extract from his speech:
"You have shown what history teaches us, that at defining moments like this one, the change we need doesn't come from Washington. Change comes to Washington. Change happens -- change happens because the American people demand it, because they rise up and insist on new ideas and new leadership, a new politics for a new time. America, this is one of those moments. I believe that, as hard as it will be, the change we need is coming, because I've seen it, because I've lived it.” 

But my question is, is that a certain rhetorical device? Yes I am aware that there are rhetorical device for when a word is repeated at the end of a sentence or at the beginning of at sentence and so forth. But what about the word "moment" in the extract, the fact that he repeats it two times in only three lines must give some sort of effect? But I don't know what to called it, except for repetition (which does not sounds as fancy as all the other rhetorical devices).

Thanks in advance