Who said "Change is the only constant."?

This quote is attributed to Arrow.

Change is the only constant. - Arrow

"Change is the only constant."

Arrow Change

"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."

"Change brings new opportunities."

"Every day is a new opportunity."

"Healing doesn't mean forgetting."

"You either get better or you get bitter."