Because the ancients paid attention to neat, symmetrical and even rhyming sentences, such as "gentleman's righteousness, villain's benefit" is probably Confucius' vernacular, but it is very neat and symmetrical. More importantly, a few simple sentences accurately express an idea. Another example is Confucius' Yi Zhuan, which says that "a gentleman strives for self-improvement through hard work" and "a gentleman carries things with virtue" (all the other 62 hexagrams are imitated in this way). The sentence patterns are the same and easy to spread. This is why many expressions of the ancients later became idioms (mostly four words), for example, Lao Tzu said that "human nature is as good as water." It is conceivable that if the highest goodness is expressed in vernacular Chinese, it will certainly not last long. Confucius said, "Words without words are far away", so what the ancients said thousands of years ago can be passed down to today, but you probably don't know what scholars like Qian Mu, Feng Youlan, Chen Lai and Chen Guying said.