"There is water in a big river, but there is no water in a big river" is a folk proverb, and the specific source cannot be verified.

The water from the big river comes from the small river. If the river has a lot of water, the river will be full. On the other hand, if there is no water in the big river, there is no water in the small river. It emphasizes the interdependence between the whole and the part, and between the whole and the part from a new angle.