Who said "I shake and shiver, but I never give up."?

This quote is attributed to Courage the Cowardly Dog.

I shake and shiver, but I never give up. - Courage the Cowardly Dog

"I shake and shiver, but I never give up."

Courage the Cowardly Dog Perseverance

"Courage, the cowardly dog."

"What's wrong, Muriel?"

"Oh, the things I do for love."

"Stupid Eustace!"

"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."