How we cite our quotes: All quotations are from the Japanese to English translated subtitles of Seven Samurai.
Quote #1
RIKICHI: And you think they'll listen? Have you forgotten what we had to go through to keep the little rice that we have now?
He's stressing how little the bandits care for them: how few moral rules they have. Samurai the answer to their problem because they are principled enough to help a powerless village: exactly the kind of principles that simple mercenaries would reject.
Quote #2
GISAKU: What's the use of worrying about your beard when your head's about to be taken?
Gisaku's stressing that one's ethics or principles are only as good as the world lets them be. Sometimes, you have to make choices, and that might mean sacrificing a value you considered pretty important.
Quote #3
KIKUCHIYO: Looking at a worm like her I get sick. Wretched, helpless. I never want to be like that. I want to be reckless, daring...
KAMBEI: Then you just keep feeling like that until the bandits come.
Kambei echoes Gisaku's sentiments about ethics being only as applicable as the situations. If you have to give them up when trouble hits, then they're not worth very much. Kikuchiyo might talk a big game, but as far as Kambei's concerned, nothing counts until things get nasty.