Diligent in state: it means doing one's best for water conservancy.

Be frugal at home: live frugally at home. ?

Interpretation: I can work hard for my country and save money at home.

Since ancient times, China has regarded frugality as the virtue of self-cultivation and governing the country. There is a saying in the Book of Changes that "it is difficult for a gentleman to be frugal". Whether the ancients can be thrifty or not is related to the survival of national strength. People are encouraged to do their duty, work hard, advocate thrift and oppose waste. Of course, in today's modern civilization, material is extremely rich, and people can't ignore the enjoyment of life, but the premise is not extravagance and waste. The story we often tell now is that Dayu managed the water and failed to enter the household, which is a model of "serving the country diligently". ?