Who said "The will to keep going matters most."?

This quote is attributed to Luffy.

The will to keep going matters most. - Luffy

"The will to keep going matters most."

Luffy Perseverance

"I'm gonna be King of the Pirates!"

"A man's dream will never die!"

"I don't care what happens to me, I'm gonna help my friend!"

"Being alone is better than being with the wrong people."

"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."