The expression might mean that a good pupil/student should learn everything that the master/teacher knows and then learn more. If the student learns more than the master, then the student can become a master and the new students will learn more than the previous generation, and the world will have more knowledge. If a scientist learns only what the teacher taught him/her, then the scientist will not learn more and the science will not improve.

For me it means more like the master is giving you some knowledge that comes directly from him, but also (and more important ) he has to teach you how great is the 'hunger to know' more stuff and give you the tools to keep discovering more and more on your own. So, according to our conception of life, age, etc, you are supposed to have more time than your master to find out a huge amount of things beside the ones he talked to you about. So, 'poor' means that he (the pupil) will probably regret the fact that having the resources he didn't take advantage of it. =) But its always relative, you feel whatever you choose to feel in the end !

it could mean that the students who dont pass their master are not good enough or dont have the required qualities maybe u mean that you feel sorry for them like when we say the poor girl always gets the blame for everything that goes wrong. hey poor also means not rich but i dont think u mean that.

In this context poor means unfortunate.

I guess it means, that if a pupil does never surpass his teacher, he will be a sad person.