When a student partakes in martial arts lessons this is how I see it in terms of the roles that the student and the instructor are supposed to take. Lets say you're using a car to get from point A to point B. In this case the sensei or the instructor would be steering the car, guiding it, telling it what directions it should take to get to point B. The student would be the engine, providing the drive, the effort and hard work that it takes to get to point B. The student has to do the work to learn the martial arts, the student has to put forth the effort and hard work to gain knowledge, skill, and ability in the martial arts, the instructor can't do it for them, but the instructor has to provide the guidance, the instructor has to tell the student what to do to make sure the student is doing it right, to make sure the student is working in the right direction.