Who said "I've never backed down from a challenge, and I never will."?

This quote is attributed to Captain America.

I've never backed down from a challenge, and I never will. - Captain America

"I've never backed down from a challenge, and I never will."

Captain America Perseverance

"I can do this all day."

"When I first arrived at Camp Lehigh, I was just a scrawny kid from Brooklyn. But I learned that being a soldier isn't about size or strength."

"There are men laying down their lives. I got no right to do any less than them."

"I'm just a kid from Brooklyn. I can't do this."

"Perseverance is the key to success."

"Don't give up on what you believe in."

"I've been through worse."

"You learn to live with the pain."