To know, is to know that you know nothing. That is the meaning of true knowledge. When you say something, say what you know. When you don't know something, say you don't know. That is knowledge.
The superior man will watch over himself when he is alone. He examines his heart that there may be nothing wrong there, and that he may have no cause of dissatisfaction with himself.
The nobler sort of man emphasizes the good qualities in others, and does not accentuate the bad. The inferior does the reverse. . . . The nobler sort of man pays special attention to nine points. He is anxious to see clearly, to hear distinctly, to be kindly in his looks, respectful in his demeanor, conscientious in his speech, earnest in his affairs. When in doubt, he is careful to inquire; when in anger, he thinks of the consequences; when offered an opportunity for gain, he thinks only of his duty.
A man should demand much from himself, but little from others. When you meet a man of worth, think how you may attain to his excellence. When you meet an unworthy one, then look within and examine yourself.
Not to converse with a man worthy of conversation is to waste the man. To converse with a man not worthy of conversation is to waste words. The wise waste neither men nor words.