《墨子·47章 贵义》
墨子说： 商人到四方去，买卖的价钱相差一倍或数倍，即使有通过关卡那种艰难，碰见盗贼那种危险，也一定去做买卖。
子墨子曰： 商人之四方，市贾信徙，虽有关粱之难，盗贼之危，必为之。
Mozi said: Businessmen travel far and wide, and the prices of their goods vary by a factor of one or several times, but they still do business despite the challenges of having to pass through checkpoints and the dangers of encountering thieves.