Gyohak Sangjang (敎學相長) means that we grow together through learning and teaching. There is also learning in teaching, so it also means not to be arrogant. It is reminiscent of the Korean proverb, ‘The more the rice ripens, the more it bows its head.’ This means that no matter how deep your studies are, you will realize your own shortcomings and learn quite a bit while teaching.