I can't think of anything that anyone has ever accomplished without having some sort of self-discipline. Without knowing how to work for it. Without learning how to earn it.
I talk to my friends who are writers. I say, "Well, how do you do it?"
Most all of them will say, "I force myself every day to sit down and write for at least two hours. Whether something comes out of it or doesn't come out of it, whether I finish my fifty pages or two, I sit down and I do that because I have to make myself do it."
That's what a work ethic is.
If you want something, if you want to achieve success in any area of life, you must apply your discipline and your work ethic. Because discipline is what helps you consciously do things in order to reach a desired goal.
~ Cameron Díaz (The Body Book)
"Personal discipline is a most powerful character quality."
~ Elizabeth George