然後君得聞其過失也。聞其過失而改之, 見義而從之, 所以永有天下也。

The governments of ancient sage-emperors had systems that recorded errors and mistakes committed by rulers, and court musicians sang adages and aphorisms to remind emperors of the righteous ways of governing. Ordinary folks could be heard muttering complaints on rulers by the roadside, businessmen and travelers were talking about the government's wrong policies and faulty actions in the marketplace. 

Emperors were willing to hear all the comments and were able to correct mistakes, and to follow whatever suggestions that are right and justified. That's why they enjoyed longevity of their monarchies under heaven.