The Master said, “A true teacher is one who, keeping the past alive, is also able to understand the present.”
(Analects 2.11)

By three methods we may learn wisdom: first, by reflection, which is noblest; second, by imitation, which is easiest; and third, by experience, which is the most bitter.

By three methods we may learn wisdom: first, by reflection which is noblest; second, by imitation, which is the easiest; and third, by experience, which is the bitterest.

He who knows all the answers has not been asked all the questions.

To know that you know, and to know that you don't know - that is the real wisdom.

The man of wisdom is never of two minds;
the man of benevolence never worries;
the man of courage is never afraid.