《资治通鉴·唐纪·唐纪十》
魏徵回答说： 我认为事情不可行，所以谏阻；陛下不听从谏阻而我如果答话，那么事情便得到施行，所以不敢应答。 
魏征对曰： 臣以事为不可，故谏；若陛下不从而臣应之，则事遂施行，故不敢应。 
Wei Zheng replied: I believe that the matter is not feasible, so I remonstrated; if Your Majesty did not listen to the remonstrance and I had responded, then the matter would have been implemented, so I did not dare to respond.