Xerxes: You Greeks take pride in your logic. I suggest you employ it. Consider the beautiful land you so vigorously defend. Picture it reduced to ash at my whim. Consider the fate of your women.
Leonidas: Clearly you don't know our women. I might as well have marched them up here, judging by what I've seen.
Xerxes is telling Leonidas to use his logic and realize that surrender is his only option.