Who said "I've learned that vulnerability is not weakness."?

This quote is attributed to Iron Fist.

I've learned that vulnerability is not weakness. - Iron Fist

"I've learned that vulnerability is not weakness."

Iron Fist Strength

"I am the living weapon. I am Iron Fist."

"I've trained my entire life for this moment."

"The chi flows through all living things."

"I need to protect the innocent."

"Strength comes from within."

"A woman should be proud of who she is."

"A strong woman can overcome anything."

"The only thing I'm good at is killing."