It means that a gentleman has a sense of shame when doing things and stops before reaching perfection.

It comes from Zi Lu, the Analects of Confucius: "It's a scholar to be ashamed of yourself and make it work in all directions without humiliating your life." It means that you have a sense of shame when you do things, and you can complete the mission entrusted by the monarch by sending foreign parties. You can be called a scholar.

Stop at perfection comes from The Book of Rites University: "The way of a university is to be virtuous, to be close to the people and to stop at perfection." It means that the purpose of self-cultivation is to carry forward aboveboard moral character, to make people abandon the old and draw new ideas, and to make people reach the most perfect state.

Extended information:

"Doing one's own thing is shameful" Example: Song and Lu Jiuyuan's Book with Xu Ziyi: "Brothers are honest in nature, and doing one's own thing is shameful, so it is not true."

"stop at the best", stop: stop, restrain. Because both good and evil exist objectively, there are great good, small good, great evil and small evil, and good is always good and evil is evil. The so-called supreme good is the ultimate of good, but in fact it is closer to evil, so those with small ability pursue small good, while those with great ability pursue great good, but it is not the ultimate good. If there is really perfection, knowing how to stop and restrain it may be true perfection.

Resources:

Baidu Encyclopedia-Doing one's own thing is shameful

Baidu Encyclopedia-Stop at perfection.