Have you ever watched The Princess Bride? There's a scene in it where Inigo Montoya has been stabbed repeatedly by the Six-Fingered Man. He's in pain, bleeding, on the way to death. Then, her remembers his mission, and begins to repeat, "Hello, my name is Inigo Montoya. You killed my father. Prepare to die." He rises up, an returns to the duel.
With each repetition, Inigo gains strength and speed. He's just as physically wounded, but he's up and fighting again.
In this case, Inigo inspired himself, but the same idea operates about as well if someone else reminds you of why you are there, what you're doing, and what it is you've got that's worth living for...