"Unity of knowing and doing ends in perfection" means the unity of thought and behavior, theory and practice, and the pursuit of perfection. "The unity of knowledge and action ends in perfection", which is simply understood as having both morality and words, and being consistent in words and deeds.
"Unity of knowledge and action" comes from "The Book of Practice" written by Mr. Wang Yangming, a thinker of the Ming Dynasty, which implies a high degree of unity of thought and action.
"stop at the best" comes from "The Book of Rites University". The original text: The way of a university is to be virtuous, to be close to the people and to stop at the best.
Vernacular translation: The purpose of a university is to promote aboveboard moral character, to make people discard the old and draw new ideas, and to make people reach the most perfect state. Extended information
The background of the integration of knowledge and practice is put forward:
After Wang Yangming realized Taoism in Longchang Town, xiuwen county County, northern Guiyang, he deeply understood the truth of life, which was a kind of enlightenment after hard thinking. Wang Yangming believes that the attitude of mind determines the way of behavior and the world view, such as the story of Liezi's "suspicious neighbor stealing axe". From then on, he parted ways with Zhu Xi's theory and established the beginning of the great success of the mind system.
Wang Shouren's theory of the unity of knowledge and action is mainly aimed at Zhu Xi's study, which is contrary to Zhu Xi's thought. Oppose Cheng Zhu's Neo-Confucianism's theory of "dividing knowledge and practice into two parts, thinking that you must be a prophet and then you can do it" and the resulting style of study of "emphasizing knowledge and ignoring action".
Cheng Zhu's Neo-Confucianism, including Lu Jiuyuan, advocates "knowledge comes first", which divides knowledge into two parts, and holds that knowledge must be understood before practice. Wang Shouren advocated the unity of knowing and doing in order to correct Zhu Xue's bias.
Reference: Baidu Encyclopedia-Unity of Knowledge and Practice