《北史·列传·卷四十四》
可为世人起劝戒作用的，都议论他的得失优劣；对世人没什么帮助的，就不去论说。 
澹弟彦玄，位洧州司马。
That which may serve as a warning to the world, I will discuss its merits and defects; that which is of no use to the world, I will not discuss.