《贞观政要·卷八·论刑法》
如果国君和臣子之间互相怀疑，那么老百姓就会疑惑；臣下不易驱使，君上就得劳神费心了。 
上人疑则百姓惑，下难知则君长劳矣。 
If the monarch and the courtier doubt each other, the people will be doubtful. It will be hard to control the courtier, so the monarch will have to spend his mind and energy on it. 