Felicity: Guess what I majored in. Hint - not the secretarial arts!
Oliver: Felicity! If I'm going to be Oliver Queen, CEO, the I cannot very well travel down 18 floors every time you and I need to discuss how we spend out nights.
Felicity: And I love spending the night with you...three...two...one. I worked very hard to get where I am and it wasn't so I could fetch you coffee!
Diggle: Well, it could be worse. My secret identity is his black driver.

I would have emailed, but this isn't exactly an email hot spot.

Oliver: If we're gonna do this, it has to be about Tommy. I need to be the man he hoped I could be. Now you two have helped me take the first step.
Felicity: So what's step two? I'm game for anything as long as it doesn't involve skydiving, and I'm pretty down on landmines now, too.
Oliver: The city still needs saving, but not by The Hood. Not by some vigilante who's just crossing names off a list. It needs something more.
Diggle: It needs a hero, Oliver.
Felicity: It's too bad The Hoods kind of ruined your nickname.
Oliver: No, it's good. I don't want to be called The Hood anymore.
Diggle: Okay. So what do you want to be called?

Besides, Army regulations. A brother never lets a soldier go into battle alone.

I take back every joke I made about you sticking a tracking device in your boot.

Diggle: What did you want?
Felicity: Is that any way to treat a girl who just walked up six flight of stairs?
Diggle: No, it's not. Welcome.

Oliver: Do you want Lauton arrested?
Diggle: No.

Then let's talk about Helena. Oliver, if you didn't still have feelings for this girl you would have thought of a different solution than letting her extort you into killing someone.

Felicity: Where are we going to get our hands on a rare Spanish antiquity?
Diggle: You really have no idea how rich his family is, do you?

Diggle: Oliver, if this were anybody else you'd be hooded up right now on your way to have an Arrow side chat with them.
Oliver: This isn't anybody else. This is my mother, and I know her.

Diggle: Woah. That's a neat trick. You gonna teach me that someday?
Oliver: No.

Diggle: Find what you're looking for?
Oliver: Took down three Vertigo pushers tonight, Diggle. Last one finally knew a name. The Count.
Diggle: The Count. That's worse than The Hood.

Arrow Quotes

Laurel: Helena, you don't have to do this.
Helena: Yes, I do. Because once you let the darkness inside, it never comes out.

Oliver Queen is dead, eventually to be reborn as Ra's al Ghul. For now, only the Arrow, Al Sah-him, shall remain. Al Sah-him, Heir to the Demon.

Ra's al Ghul