"Deep thinking generates knowledge.
Idleness and carelessness generate worry.
Cruelty and arrogance generate resentment.
Worry and grief generate illness....
When you think about something 
and don't let got of it,
Internally you will be distressed,
externally you will be weak.
Do not plan things out in advance
Or else your vitality will cede its dwelling.
In eating, it is best not to fill up;
In thinking, it is best not to overdo.
Limit these to the appropriate degree
And you will naturally reach it [vitality]."
 " When you are tempted to use words as weapons
   ask yourself what you hope to gain."