緇門警訓 9.139

9.139

○廁中不可畫壁書字。每見尊宿老成。路逢字紙在地。即收置淨處。或拋在水中。蓋尊重字畫。不忍狼籍。況書臭廁中。豈不折福。

Inside the privy, one must not draw on the walls or write characters. Whenever one observes venerable elders of mature conduct encountering paper with writing on the ground along the road, they immediately collect it and place it in a pure place, or cast it into water, because they revere written characters and cannot bear to see them profaned. How much more, then, would writing in a foul privy diminish one's merit?