First of all, we all know the book Mencius. Although Mencius did not write it himself, it was written by his disciples, but the content described in it is really Mencius' words and deeds. From the book, we can see that Mencius first sublimated Confucius' thought of "benevolence" into the thought of benevolent government in the political field, which made Confucianism have a clear proposition in politics, making Confucianism no longer just belong to the ideological field, but let Confucianism and its disciples exist as a political group. Therefore, many people want to take the imperial examination, study or be an official, and they must learn Confucianism and some Confucian classics.
Secondly, more than 2,000 years ago, the human society in the pre-Qin period was still in the transition stage from slave society to feudal society, but Mencius' people-oriented thought was simple at that time, so it was very remarkable that he could have such an idea, because the society at that time was the law of the jungle, and the big country merged with the small country, only the strong could be king, and all capable people were thinking about how to get more. Few people would think about how to benefit the people, so Mencius' thoughts at that time were not adopted, but with the passage of time, history has proved Mencius' thoughts and proved his correctness.
Finally, Mencius enriched our language range, because he created many idioms and famous sayings, which are still used in our daily life. Therefore, through his own research, Mencius raised the thought and realm of Confucianism to a higher level, so he was also honored as the "Asian sage" of Confucianism, and his position in the Confucian school was second only to that of Confucius.
The above is just Bian Xiao's personal opinion. Please forgive me if there is any mistake.