What does it mean to teach those good ancestors?

"The teaching of good ancestors" refers to guiding others to start from kindness, which is called teaching. This sentence comes from Xunzi's "Cultivation".

In this paper, Xunzi used the exegetical method of meaning boundary (that is, defining and establishing boundary theory), and distinguished synonyms of 23 words by comparison.

Xunzi's self-cultivation excerpt: what is good for ancestors is called teaching, and what is good for people is called obedience; Bad ancestors are called flattery, and bad others are called flattery. Yeah, yeah, yeah, yeah, yeah, yeah, yeah, yeah, yeah, yeah. Hurting a good man is called slander, and hurting a good man is called a thief. Right, right, wrong, wrong, wrong, wrong, stealing goods is called stealing, hiding is called cheating, easy to say is called birthday, fun is uncertain, and abandoning righteousness is called thief. Listen more and learn more, listen less and learn more. It is more common to say idle things, but it is less common to say ugly things. It's hard to get in, but easy to forget. Less is the rule, more is chaos.

Guiding others out of kindness is called teaching, and agreeing with others out of kindness is called obedience; Unscrupulous leading others is called flattery, and unscrupulous agreeing with others is called flattery. Admitting right is right, wrong is wrong, thinking wrong is right, and right is asymmetric. This is called wisdom. Those who harm sages call it slander, and those who kill sages call it cruelty. Right is right, and wrong is wrong. This is called integrity. Stealing goods is called stealing, hiding is called fraud, changing words is called vanity, always changing, leaving behind is called impermanence, giving up loyalty and protecting one's own interests is called cruelty. What you know is deeper, and what you know is not so superficial. Knowledge is more familiar, but less knowledge is shallow. What is difficult to improve is called slow action, and what is easy to forget is called omission. Simple and orderly is called good governance, and complicated and cumbersome is called waste.