You have not failed until you have quit trying - Gordon B. Hinkley

"You have not failed until you have quit trying, and please remember that your example in your home will be a more persuasive sermon than will any other kind of preachment."

Gordon B. Hinkley, Live Up to Your Inheritance, 1983 Semiannual General Conference for The Church of Jesus Christ of Latter-day Saints

https://www.churchofjesuschrist.org/study/general-conference/1983/10/live-up-to-your-inheritance?id=p25&lang=eng#p25