Who said "Change is the only constant in life."?

This quote is attributed to Guardians of the Galaxy.

Change is the only constant in life. - Guardians of the Galaxy

"Change is the only constant in life."

Guardians of the Galaxy Change

"I'm your friend, man. I do this because you're my friend."

"Sometimes the thing you fight the most is the thing you need the most."

"We are Groot."

"You're welcome for saving the galaxy, by the way."

"Change brings new opportunities."

"Every day is a new opportunity."

"Healing doesn't mean forgetting."

"You either get better or you get bitter."