《后汉书·列传·光武十王列传》
古书说： 田猎不宿，食饮不享，出入不节，则木不曲直。 
传曰： 田猎不宿，食饮不享，出入不节，则木不曲直。 
An ancient book says: If hunting is not done at night, food and drink are not enjoyed, and going in and out is not done in moderation, then the trees will not grow straight.