Who said "Fear is the mind killer, but it's also the mind sharpener."?

This quote is attributed to Arrow.

Fear is the mind killer, but it's also the mind sharpener. - Arrow

"Fear is the mind killer, but it's also the mind sharpener."

Arrow Fear

"My name is Oliver Queen. After five years in hell, I have come home with only one goal: to save my city."

"I'm not the man I was."

"You have failed this city."

"I'm a monster."

"Face your fears with courage."

"You can't live your life in fear."

"Snakes. Why'd it have to be snakes?"

"Fear is just another obstacle to overcome."