To be austere, without bragging about it

When you have become adjusted to simple living in regard to your bodily wants, do not preen yourself about the accomplishment; and so likewise, if you are a water-drinker, do not on every occasion say that you are a water-drinker. And if ever you want to train to develop physical endurance, do it by yourself and not for outsiders to behold; do not throw your arms around statues, but on occasion, when you are very thirsty, take cold water into your mouth, and then spit it out, without telling anybody.