《后汉书·列传·桓荣丁鸿列传》
臣听说天不可以不刚，不刚则三光不明；王不可以不强，不强则宰牧纵横。
臣闻天不可以不刚，不刚则三光不明；王不可以不强，不强则宰牧从横。
I have heard that Heaven cannot fail to be severe, for if it is not severe, then the three luminaries will not shine brightly; a king cannot fail to be strong, for if he is not strong, then the governors and shepherds will act with impunity.