Diggle: That's just the thing. Once we let the ends justify the means, that's just the first step.
Malcolm: Towards what?
Diggle: Becoming you.

Diggle: He's not coming back, Oliver. I know you don't want to believe it, Laurel, God knows I don't but, he's not coming back.
Laurel: Are you? Are you coming back?
Diggle: I don't know. For the first time since I met Oliver Queen I don't know what happens next. I know it's silly, but I still like to think of myself as Oliver's bodyguard. I just couldn't protect him. It's funny. He was worried something would happen to me.

Diggle: OK. The point is, if we're going to do this without Oliver, Felicity, we have to trust each other.
Felicity: You don't get it. There is no 'this' without him. It's done. I'm done.

Diggle: I'm more of a glock kind of a guy.
Roy: I didn't say anything.

Cisco: Are you OK?
Diggle: My daughter's mother tried detonating a bomb inside a man's head and now he's trying to kill her.
Cisco: So that would be a no.

Lyla: You only call me sweetie when you want something.
Diggle: Is it working?

Diggle: If this is an ARGUS thing, Lyla's gonna want it to stay that way.
Oliver: Then tell her to stop letting people get killed in my city.
Diggle: You really don't care about my marriage, do you?
Oliver: Well I would, if you and Lyla were still married.

This thing with Palmer, it's messing with his head, Felicity, and that's dangerous.

Oliver: John, I don't want to die down here.
Diggle: So don't, Oliver.

Laurel, we'll know. I know this doesn't count for much but, me and Lyla, we're naming the baby Sara. We will never forget.

Listen, Sara was my friend, too and if you think you're going after her alone you couldn't possibly be more wrong.

Diggle: Oliver you'd be dead ten times over if it wasn't for me!!!
Oliver: You're right. But this is my crusade and this is my decision.

Arrow Quotes

Are you done?
Oliver; Yeah, I'm done. I'm done taking the blame and I'm done caring. Why don't you go have a drink. Get wasted. Go to Verdant. I'll pay for it. I have loved you for half of my life but I'm done running after you.

Laurel

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