Who said "The only failure is giving up."?

This quote is attributed to Arrow.

The only failure is giving up. - Arrow

"The only failure is giving up."

Arrow Perseverance

"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."

"Perseverance is the key to success."

"Don't give up on what you believe in."

"I've been through worse."

"You learn to live with the pain."