人知糞田,莫知糞心。
People know that they must fertilize their fields; none know that they must fertilize their hearts.
端身正行,全以至今。
Those who hold themselves erect and walk uprightly will preserve themselves intact through everything.
見亡知存,見霜知冰。
Observing cases of destruction enables us to know how to survive; observing frost allows us to know the nature of ice.
On Fitting Actions to Circumstances