Student is the one who wants to learn new things, and therefore studies towards that goal. In this process he/she gets the knowledge. Teacher is the one who teaches the gained knowledge to his/her students. While doing this, teacher confirms his knowledge to be solid. But, here Teacher also learns his/her weak points. Thus, Teacher gets the knowledge that confirms his/her previous understanding and also gets the knowledge of which topics need to be improved.
Thus in education process, student is becoming better and also becoming a Teacher. And, teacher is becoming better and better and always remains a student.
This is an amazing relationship. May be that is why the Upanishads have the prayer..
saha nau avatu,,, etc. which applies to both Student and Teacher both.