This statement is made almost off-hand by Hippolyta at the start of the film when she tries to convince a young Diana that war is nothing to hope for. It's a strange statement to be made in a movie that is at least partially a war-film. However, it is the final driving message of the film, that Diana herself realizes by the end. War merely breeds more war, and sometimes the greatest acts of heroism have nothing to do with fighting. This is exemplified in the heart-breaking moment when Steve courageously sacrifices himself. It's this act that spurs Diana to embrace a more optimistic outlook on mankind as a whole.

The double playback of his farewell to her is used powerfully to remind Diana, that not all men are selfish war-mongers. Steve isn't sacrificing himself for her, he already knows she's immune to the poisonous gas. So rather than it be some sort of epic gesture of romantic love, instead it's an act of pure selflessness for what he believes is right, giving up any future he might have had with her, in order to save thousands of nameless and faceless people. And it's this moment, when played for the second time, with the realization of what Steve had really done, that causes Diana to set aside her wrath, and show mercy to Doctor Maru, and declare that she believes in something far greater than war and judgement.