If language is not correct, then what is said is not what is meant. If what is said is not what is meant, then what must be done remains undone. If this remains undone, morals and art will deteriorate. If justice goes astray, the people will stand about in helpless confusion. Hence there must be no arbitrariness in what is said. This matters above everything.
Right vs. popular
The superior man understands what is right. The inferior man understands what is popular.