This is a famous saying of Durant, which is aimed at teachers and of course applies to students. It specifically means:

1: In the process of teaching, a teacher will find that his knowledge can no longer adapt to the psychological and knowledge structure characteristics of children in this era, and he has fallen behind. At this time, teachers should actively learn and know their own education and teaching activities with the concept of lifelong learning, so as to keep pace with the times and not be eliminated.

As a student, you should also study actively;

This sentence is to tell teachers that they must have the idea of lifelong learning and find that personal shortcomings are progress in themselves! Insist on continuing education, so as not to be eliminated!

Please refer to.