If it seems someone is out to get you, they are. (Season 7, Episode 22)

Rule #40

Never accept an apology from someone who just sucker punched you. (Season 9, Episode 16)

Rule #42

First things first. Hide the women and children. (Season 7, Episode 23)

Rule #44

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

Rule #45

Never leave behind loose ends. (Season 3, Episode 24)

Rule #45

Sometimes you're wrong. (Season 7, Episode 24, titled "Rule Fifty-One")

Rule #51

Never trust a woman who doesn't trust her man. (Season 9, Episode 7)

Rule #69

You do what you have to for family.

Unwritten Rule

I know rule 62 is to always give people space when they get off the elevator but this is really important and I don't want to waste any time.

Abby

Welcome aboard, probie.

Gibbs

Gibbs: What are SecNav's orders?
Vance: Now that we have Parsa - press him for intel. Enough to disable his entire terrorist network.
Gibbs: How hard?
Vance: Whatever it takes.

Vance: So, what are you gonna tell her? (Gibbs turns to face him) Lee a hero or a villain?
Gibbs: Both.

NCIS Quotes

Bishop: Seriously? How'd you get that?
Tony: Well, it's like Gorillas in the Midst. You'll get to understand his grunts.

Torres: When I break out the glass, maybe I can rip out the bars.
Bishop: With what? Your superhuman strength?