《管子·明法解》
所以君臣之间的高下地位，有如天之与地；其划分的差别，有如白之与黑。
故君臣相与，高下之处也，如天之与地也；其分画之不同也，如白之与黑也。
Therefore the difference in status between the king and the ministers is like that between heaven and earth; the difference between each of them is like that between black and white.