Even if you seek to harm an enemy,
You should remove your own defects and cultivate good qualities.
Through that you will help yourself,
And the enemy will be displeased.

From your place of darkness observe the defects of others. See but do not appear to see; listen but do not seem to listen; know but do not let it be known that you know. When you perceive the trend of a man's words, do not change them, do not correct them, but examine them and compare them with the results.