《资治通鉴·隋纪·隋纪七》
过不久，炀帝向苏威询问征伐高丽的事情，苏威想让炀帝了解天下有很多盗贼的情况，就回答说： 现在征辽之事，但愿不要发兵，只要赦免群盗，自然可以得到几十万人，派他们去东征，这些人对被赦免罪过感到高兴，会竞相立功，高丽就可以被平灭。 
顷之，帝问威以伐高丽事，威欲帝知天下多盗，对曰： 今兹之役，愿不发兵，但赦群盗，自可得数十万。遣之东征，彼喜于免罪，争务立功，高丽可灭。 
Not long after, Emperor Yang asked Su Wei about the campaign against Koguryo, and Su Wei, wanting to make Emperor Yang aware of the existence of a huge number of thieves in the empire, replied: "Now, concerning the campaign against Liao Prefecture, if only no troops were sent, all of the rebel thieves were pardoned, we would naturally obtain several hundred thousand men, and if they were sent on the expedition in the east, would be delighted at having their offenses pardoned, they would compete to perform meritorious service, and Koguryo could be pacified.