Perseverance is an active principle, and cannot continue to operate but under the influence of desire. — William Godwin
Failure after long perseverance is much grander than never to have a striving good enough to be called a failure. — George Eliot
Furtherance is the agreement of all that is just. Perseverance is the foundation of all actions. — Lao Tzu
Perseverance is the hard work you do after you get tired of doing the hard work you already did. — Newt Gingrich