I-Ching commentary:

The nature of water is to flow downward, the nature of wood is to float upward; when water rises above wood, it can destroy wood, and when wood descends below water, it can be destroyed by the moisture. This is the image of great excess. What superior people see in this is that just as a great excess of moisture can destroy wood, so can a great excess of talent and intelligence in people destroy their character. Therefore, they take the model of water rising above wood in the sense of standing alone without fear, and take the model of wood descending below water in the sense of concealing themselves and being free from distress; thus they accomplish the will of a person of exceeding greatness, and perfect the character of a person of exceeding greatness.
(Source: Taoist I Ching, Yiming Liu, tr. Thomas Cleary)