"Being good and saving the lost" was proposed by Le Zhengke.

"Exerting good qualities to save mistakes" is an important teaching concept, which aims to emphasize that educators should be good at discovering and correcting students' mistakes. This idea originates from a famous saying in "Book of Rites·Xue Ji": "Knowing one's heart can save one's lost things; one who teaches can be good and can save his lost ones." This sentence means that education Teachers need to have a deep understanding of students' inner world in order to better discover their shortcomings and help them correct their mistakes. The purpose of education is not only to impart knowledge, but also to promote students' strengths, help them correct their mistakes, and grow into better people.

This teaching concept still has important guiding significance for modern education.