Plato:
“When men speak ill of thee, live so that nobody will believe them.”

Another one I love is by Marjorie Pay Hinckley:
“The trouble with the world and the trouble with you and me is that we don’t love each other enough. And if we do, we don’t bother to show it, or we don’t bother to say it. If the world is to know love, it has to begin at home. It has to be in your heart and in mine. And the place to begin is home.”

And this one is also by Sister Hinckley:
“You either have to laugh or cry. I prefer to laugh. Crying gives me a headache.”