《六韬·虎韬·金鼓》
武王问太公说： 率领军队深入敌国境内，敌我双方兵力相当，正好碰上严寒或酷暑，或者是每日大雨下了十日还未停止，造成沟堑营垒全部毁坏，山险要隘不能守备，侦察哨兵懒散松懈，士兵疏于戒备。
武王问太公曰： 引兵深入诸侯之地，与敌相当，而天大寒甚暑，日夜霖雨，旬不止，沟垒悉坏，隘塞不守，斥堠懈怠，士卒不戒，敌人夜来。
King Wu asked Grand Master Jiang: What if our army is evenly matched with the enemy in enemy territory, and we encounter extreme cold, heat, or ten days of heavy rain, which destroys our trenches and fortifications and makes it impossible to guard strategic points in the mountains? What should our army do if enemy forces launch a surprise attack at night while our defenses are lax and our soldiers are unprepared and confused?