Who said "I've learned that vengeance only leads to more pain."?

This quote is attributed to Arrow.

I've learned that vengeance only leads to more pain. - Arrow

"I've learned that vengeance only leads to more pain."

Arrow Peace

"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."

"Peace comes from a good conscience."

"Life is too short to hold grudges."

"A man's home is his sanctuary. It should be treated as such."

"The world is chaotic enough. At least your home should make sense."