《笑林广记·贪吝部》
教书先生借口送饭晚了，要斥责他。仆僮说： 是天下雨路滑的缘故。 
师以其来迟，欲责之。僮曰： 天雨路滑故也。 
The teacher used the late delivery of the meal as an excuse to scold him. The servant said: It was because the road was slippery due to the rain.