User blog comment:Monkey.D.Me/O RLY??/@comment-4899461-20120822194504

I'm glad someone else was able to recognize the importance of this quote.

From Water 7 through the Post-war arc, the series was about how Luffy wasn't strong enough to protect his crew or his brother. Every one of the villians in that period remarked about how weak Luffy was, and most threatened to or nearly did kill his crew. For many of the fights in that period, it wasn't even about Luffy's own ambition to be pirate king, it was just about protecting his friends.

Fishman Island is about confronting the SHs with a seemingly powerful enemy. One of the recent episodes ends with an interaction between Luffy and Hody. Hody tries to tell Luffy that Luffy can't protect Shirahoshi, FI, or his friends in the plaza. Luffy declares that he will protect them. And he does because he has become much, much stronger. That's what FI island is about.

But Hody was weak by New World standards. The first person to hand Luffy his first loss in the NW is Caesar Clown. Luffy got cocky (not that he ever wasn't cocky) after FI, and in his first fight with CC, he was careless. This reminder from Zoro is that the NW is the big leagues, and Luffy can't afford to be careless. Not only for the sake of his crew, but for the sake of their ambitions too. Zoro mentions his fight with Yeti Cool Bros. and how they put him to sleep. They were careless too, not just Luffy. This reminder is that the NW is serious business.

And it's important that Zoro gives this reminder. Zoro made by far the biggest sacrifice for the crew on Thriller Bark. He made a deal with Kuma: His life for his crew's. At no point did Zoro think he could actually survive his interaction with Kuma. He just did it all to protect his crewmates, and didn't think about himself or his ambition. Zoro isn't the captain, or even the vice-captain, but the saftey of the crew is just as important to him as it is to Luffy.