《史记·七十列传·仲尼弟子列传》
吴国，它的城墙高大而厚实，护城河宽阔而水深，铠甲坚固而崭新，士卒经过挑选而精神饱满，可贵的人才、精锐的部队都在那里，又派英明的大臣守卫着它，这样的国家是容易攻打的。 
夫吴，城高以厚，地广以深，甲坚以新，士选以饱，重器精兵尽在其中，又使明大夫守之，此易伐也。 
The state of Wu has high and thick walls, a wide and deep moat, strong and new armor, soldiers who are well-chosen and full of energy, and valuable talents and elite troops are all there, and it is also guarded by wise ministers. Such a country is easy to attack.