The only way to do great work is to love what you do.
(道德高尚的人)明察安危,安于祸福,谨慎地对待去留,就没有什么能够伤害他们。
国君若真的希望人口多而不希望人口少的话,如果要蓄养姬妾,就不能不节制。[说明∶老百姓也得有老婆生孩子,别抢人家的老婆] 
The essence of causal inference is to go beyond the data and ask what would happen if we intervene.