Who said "You can't kill what's already dead inside."?

This quote is attributed to Rocket.

You can't kill what's already dead inside. - Rocket

"You can't kill what's already dead inside."

Rocket

"I'm not a part of your team, I'm a part of the tree."

"You're making me very angry. And when I get angry, Mr. Murder pants gets scared."

"I have a plan. It might be crazy, it might get us all killed, but I have a plan."

"Don't call me a thief. I prefer the term 'unorthodox entrepreneur.'"