From
韩愈《
进学解》(Han Yu, 'Explanation of Learning's Advance,' middle Tang, c. 803 CE):
业精于勤,
荒于嬉;
行成于思,
毁于随 (Work is perfected through diligence and ruined through idle play; conduct is formed through reflection and destroyed through drift). Han Yu frames the essay as a teacher addressing his students (with himself as the mock-deflated teacher); it became a standard text for exam candidates for over a thousand years.