Clean up your own mess. (Season 7, Episode 24)

Rule #45

Tony: It's obvious you're looking to hire a replacement.
Gibbs: Motive?
McGee: I don't know. Maybe you think we need the help. Three's the magic number. Who knows? But, we don't need anyone else, boss. And we don't want anyone either.
Gibbs: I was talking about the murder.

Vance: What's his ultimate target?
Gibbs: I don't know.
Vance: I've got to notify Homeland, FBI and the ATF.

Never mess with a Marine's coffee if you want to live. (Season 2, Episode 9)

Rule #23

Gibbs: Felix, did Dan take a bribe and frame Lourda for the murders?
Betts: We did some good, didn't we? We got some sandwiches inside. You guys hungry?
Pride: Sandwiches sound real good, Felix. Real good.

Gibbs: You forgot something.
Bishop: Ahh, that's not mine.
Gibbs: It's got your name on it.
Bishop: This is my NCIS application from years ago. Before I took the job at NSA. How did you know about this?
Gibbs: Your name sounded familiar. I went back and looked it up.
Bishop: That's why you took me along today. You play chess too.
Gibbs: I wanted to see if you're still up for a challenge.
Bishop: Why?
Gibbs: I'd like to keep you around. Joint duty assignment.

Never take anything for granted. (Season 3, Episode 10)

Rule #8

Always work as a team. (Season 5, Episode 5)

Rule #15

Abby: This guy was a genius! He chronicled all his exploits on his phone. It's like a master's course! Six hundred pizzas delivered to the battalion CP. He reassembled a Humvee inside the officer's club. If only I had the appropriate time and space to use the bounty of ideas in front of me.
Gibbs: The case, Abbs. The case.

Gibbs: What's that?
Ducky: His liver, riddled with inoperable tumors. It doesn't appear to have been under treatment. I'd have given him six months.
Gibbs: Made killing himself easier.
Ducky: Pity does not validate cowardice.

Vance: Bad cop?
Gibbs: You've been playing good cop all this time?

McGee: Red handed?
Gibbs: They don't come much redder.

NCIS Quotes

Tony: One other question, I know you're an expert in English history. And I was just wondering, have you ever heard of Archibald Drummond, the 17th Earl of Trent?
Ducky: The Earl of Trent. No, I can't say I have. Why?
Tony: I was just wondering. Thanks.

McGee: All right. Well you should probably know that Abby and I used to date?
Bishop: Ew. Like, each other?
McGee: Yeah.
Bishop: Wait - isn't that a violation of rule 12, never date a....
McGee: It was a long time ago. After we'd broken up, one night I went to her lab. Found a scribbled piece paper; a list. Potential boyfriends had to fulfill certain conditions by a pre-arranged date or else, goodbye.
Bishop: Such as.
McGee: Things started off relatively normal: opening the door for her, flowers, putting the seat down. Then around number 8, it gets uh...
Bishop: What?
McGee: Does she know you have these?
Bishop: Does she know you have these?
McGee: Yeah she wasn't happy when she found out.
Bishop: These are all very specific.
McGee: Yeah.
Bishop: These ideas apply to you?
McGee: No those rules weren't in place when we were together. At least I don't think so.
Bishop: What's with the two month cutoff? Abby's sabotaging herself. I've seen stuff like this before. We have to talk to her.