Who said "I've learned that change is the only constant."?

This quote is attributed to Tormund Giantsbane.

I've learned that change is the only constant. - Tormund Giantsbane

"I've learned that change is the only constant."

Tormund Giantsbane Change

"I'm a wildling. We don't kneel."

"The real war isn't between the living and the dead. It's between the free folk and the kneelers."

"Giants are real. I've seen them."

"We've been north of the Wall for thousands of years. We know how to survive."

"Change brings new opportunities."

"Every day is a new opportunity."

"Healing doesn't mean forgetting."

"You either get better or you get bitter."