Keqin tells jokes.

This sentence means: to serve the country, you must be diligent; Take charge of housework and live frugally. To put it simply, I can work tirelessly for national affairs and live a frugal life at home.

Diligent in state: it means doing one's best for water conservancy. Be frugal at home: live frugally at home.

The phrase "diligence of the country, frugality of the family" comes from Shangshu Dayu Mo.

Extended data:

Diligence and thrift is an idiom, which means thrift and thrift. From Shangshu Dayu Mo.

In "Great Mo Yu", it is recorded that Shun Di praised Dayu: "Diligent in the country, frugal at home." Shun said Dayu: You have completed the great cause of water control and worked tirelessly for national affairs, but your family life is simple and frugal; You are not complacent or boastful; You don't boast of your talent, so no one in the world can compete with you; No one in the world will compete with you if you don't brag about your achievements. So Shun wanted to pass on the throne to Dayu.

References:

Keqin Kejian Baidu Encyclopedia