《史记·七十列传·平津侯主父列传》
如果派轻便军队深入匈奴，那么军粮必定断绝；如果携带许多粮食进军，物资沉重难运，也是无济于事。
轻兵深入，粮食必绝；踵粮以行，重不及事。
If a light army was sent deep into the Xiongnu territory, the military rations would definitely be cut off; if a lot of food was carried in for the expedition, the supplies would be heavy and difficult to transport, and it would also be of no use.