Chapter 67 of the Daodejing reads: “I have three treasures, which I hold and keep. The first is compassion. The second is frugality. The third is not daring to be first under heaven.” It goes on: “Because I do not dare to be first under heaven, I can become the chief of all.”
Chapter 66 makes the same point with rivers and seas. They are kings of the hundred valleys because they lie below them. “One who wants to be ahead of the people must put himself behind them.”