《资治通鉴·唐纪·唐纪一》
陛下兴起于晋阳，远近响应，不到一年就登上帝位，只知道得天下容易，而不知隋朝失天下也不难。
陛下龙飞晋阳，远近响应，未期年而登帝位；徒知得之之易，不知隋失之之不难也。
Your Majesty started from Jinyang and responded from distant and near places, and came to the throne in less than a year. You only know that it is easy to conquer the world, but you don’t know that it is not difficult to lose the world in the Sui Dynasty.