《资治通鉴·汉纪·汉纪四十二》
况且西域之人，并没有其它的要求，使节来到汉朝，不过是供应他们膳食而已。现在若是拒绝西域各国，它们势必归属北方的匈奴人。如果各种力量联合起来，一同侵略并州、凉州，那么国家的开支将不止十亿。
且西域之人，无它求索，其来入者不过禀食而已；今若拒绝，势归北属夷虏，并力以寇并、凉，则中国之费不止十亿。
Moreover, the Western Regions people had no other requests; their envoys came to the Han Dynasty only to be supplied with food. If we now reject the Western Regions countries, they will inevitably belong to the northern Huns. If various forces unite and invade Bingzhou and Liangzhou together, then the national expenditure will not be less than one billion.