He who knows others is wise, and he who knows himself is wise. These two sentences are both from Laozi's Tao Te Ching.

The sage Confucius said: "He who knows others is wise, he who knows himself is clear, he who overcomes others is strong, and he who overcomes himself is strong." It means that those who can know others are witty, those who can know themselves are smart, those who can overcome others are strong, and those who can restrain themselves are strong.