I believe this phrase needs to be taught more than math, science, and language arts. If you are able to learn (and practice) this mental tool, nearly anything else becomes possible.
Why is this statement so true and reliable? Why is it more important than all other content that could possible be taught in school? Think about it—anything that you practice, you will get better at. You may not master anything, but the needle will move. The skill will sharpen. The account will grow. The weight will fall off. You will learn the language. Your relationship will strengthen.
The trick is identifying the goal, implementing the process, and understanding that it will never end. You will never "make it." You will never "arrive." You will either do the thing or you won't. You will either work out and improve your health and physical fitness, or you won't. You will either save for retirement, or you won't.
That doesn't mean don't set goals; it just means that without a process, you won't see the result. The distance between where you are now and the achievement of a goal is not X amount of time. That distance is the process.