Michael: (to Jack) Look, I'm going after my son. I'm going after my son and nobody is going to stop me, okay? Okay, that is my right. That is a father's right.
Jack: Michael, are you sure you're in the best place to be making decisions for all of us right now?
Michael: You got a son, Jack?!
Eko: (to Michael) And every Sunday right after mass, I would see a young boy waiting at the back of the church. And then one day, the boy confessed to me that he had beaten his dog to death with a shovel. He said that the dog had bitten his baby sister on the cheek and he needed to protect her. And he wanted to know whether he would go to hell for this. I told him that God would understand, that he would be forgiven as long as he was sorry. But the boy did not care about forgiveness. He was only afraid that if he did go to hell, that dog would be there waiting for him.
Michael: (to Jack) It's gotta be just the people who already know - you, me, Kate, Sawyer, Hurley, that's it! Anybody else... look, it puts them in more danger. You-you don't get to decide this! It's my son! It's my call! And that's the way it has to be!
Sun: (after spotting the two covered bodies) Who?
Michael: Ana Lucia and Libby.
Sun: What happened to them?
Michael: They were murdered.
Jack: Just find the trail, John.
Locke: I've lost the trail.
Jack: You don't just lose a trail! You just don't wanna find them.
Locke: Yeah, that's right, Jack. I've been running through the jungle toward the sound of gunfire because I don't care about Michael!
Jack: You know what happens if we just turn around and go back? We're never gonna see him again. And that's gonna be on us. On you. And on me.
Sawyer: (as he pulls out a bottle of wine) Whaddya say, Doc? You know, I was thinking the Irish drink when somebody died.
Jack: I'm not Irish.
Sawyer: Neither am I.
Sawyer: So, what happened out there in the jungle?
Jack: Exactly what he said happened, he found the camp...
Sawyer: I ain't talkin' about Mike. You and Freckles. Before you found him, you were gone all night.
Jack: We were caught in a net.
Sawyer: The hell's that supposed to mean?
Jack: It means... we got caught in a net.
Sawyer: That what they calling it these days?
Charlie: So, you wake up in the middle of the night, you grab your Jesus stick, race off into the jungle, you don't call? You don't write?
Eko: I'm sorry. I had work to do.
Charlie: Well, what about the church? You said we were supposed to be building it together, man.
Eko: I am supposed to do something different now.
Charlie: And what am I supposed to do?
Eko: Bring me my things.
Charlie: Bring your own things.
Eko: Charlie, please.
Charlie: You better leg it, mate... clock's ticking.
Sawyer: Got some good news for ya - Captain Arab's in, too. Cavalry rides at sunrise.
Michael: You told Sayid?
Sawyer: Yeah, I told Sayid.
Michael: You shouldn't have done that!
Sawyer: Oh, I'm sorry! I just figured if we're going to war, we'd want the one guy who's actually been in a war! That a problem?!
Michael: I want my son! You bring him to me RIGHT NOW! I want to see my boy!
Ms. Klugh: For someone who wants his son back so badly... you don't seem to know much about him, Michael.
Michael: Hey. You're not coming.
Sayid: Welcome back, Michael.
Michael: (to Sayid) I know... you want to help, right... but I gotta do this my way.
Sawyer: I never even knew her last name. Ana Lucia.
Sawyer: I screwed her.
Sawyer: It's how she got my gun. Ana... she jumped me. We got caught in a net.
Jack: Why are you telling me this, Sawyer?
Sawyer: 'Cause you're about the closest thing I got to a friend, Doc. 'Cause she's gone. Well, at least now we get to kill somebody.
Michael: What about you, man, you coming with us?
Hurley: Why would I wanna go?
Michael: Because they killed her!
Kate: Michael! Come on!
Michael: Whaddya say, Hugo?
Hurley: I'm sorry about Walt, dude, but I'm not coming.
Michael: You're sorry about...
Michael: I WANT TO SEE HIM! IF HE IS OUT THERE, YOU BRING HIM IN! YOU BRING HIM IN HERE RIGHT NOW!
Ms. Klugh: Pickett. (to Michael) You have three minutes.
Walt: They're not who they say they are. They're pretending!
Ms. Klugh: Walt! You want me to put you in the room again?
Michael: Pretending? Pretending what?
Ms. Klugh: (to Michael) If you don't bring all the people on the list, you'll never see Walt again.
Michael: Who's James Ford?
Ms. Klugh: You know him as 'Sawyer'.
Jack: What do you mean compromised?
Sayid: His actions are not those of a man who is telling the truth.
Jack: Why would he lie to us?
Sayid: Because I believe a father would do anything for his son. Because I believe that Michael may have freed Henry and because I believe he's leading you into a trap.
Jack: You believe a lot, Sayid.
Sayid: I also believe that Henry was one of them.
Throughout the entire episode, we see Michael acting a little oddly, and while the general consensus is that he's just anxious to get his son, what's really playing out is a series of tip-offs that should have led Jack (if not Hurley, Kate and Sawyer) to the conclusion Sayid came to before the funeral.
While not a comprehensive listing, these clues include the following:
1) Michael seems a little too insistent on who joins the rescue party. While three out of the four he picks are well suited for confrontations (not to mention being decent to fairly good shots), it's pretty obvious that Hurley, well...isn't.
2) Sawyer's got a point---it makes perfect sense to bring along a man who has both military training and background. Sayid is a treasure trove of skills that are well suited to the type of expedition the rescue party is about to set out on. The fact that Michael is insistent that he not come along should have given someone pause... someone other than Sayid himself, that is.
3) We know from earlier episodes that Hurley used the manifest to create the initial census, and that Locke also perused the names on that list (which is why he knew Sawyer's "real name" was James). Michael, however, never had a look at that manifest---at least, it was never mentioned. Add this to the fact that Hurley has never told his own "real name" to anyone himself (again, Locke used it in "Exodus (2)" in front of Jack and Kate, but he'd read it off the manifest), and you'd think that either Kate or Hurley himself would have noticed Michael using Hurley's "real name" while he was trying to prod him into coming along. If Hurley never told Michael his real name, how did he come to know it? He certainly didn't ask Locke.
4) Given that Michael's not exactly had the best judgement lately (and understandably so), wouldn't someone be worried that the rescue party would be led "off course" by the actions of a very biased and desperate man? And yet, everyone seems okay (at least superficially) with Michael taking the lead on this.
Put together, these clues should have been blazing DANGER signs for the members of the rescue party that Michael, to use Sayid's phrase, had been turned.