Perseverance

"People of mediocre ability sometimes achieve outstanding success because they don't know when to quit. Most men succeed because they are determined to." George E. Allen

"Perseverance is more prevailing than violence; and many things which cannot be overcome when they are together, yield themselves up when taken little by little." Plutarch

"If I had to select one quality, one personal characteristic that I regard as being most highly correlated with success, whatever the field, I would pick the trait of persistence. Determination. The will to endure to the end, to get knocked down seventy times and get up off the floor saying. "Here comes number seventy-one!" Richard M. Devos

Ecclesiastes 9:10, "Whatever your hand finds to do, do it with all your might, for in the grave, where you are going, there is neither working nor planning nor knowledge nor wisdom."