What does this sentence mean, "There are thousands of rivers and rivers, and there are no clouds in Wan Li"?

Rivers are thousands of miles away, and there are clouds in Wan Li. This poem is the rhyme of a monk in the Song Dynasty.

No matter how big or small the river is, where there is water, there is the moon. As long as there are no clouds in Wan Li, the sky in Wan Li is blue. There is water in the river and the moon in the sky. Thousands of rivers have water and thousands of rivers have moons. There are clouds in the sky, and the sky is above them. As long as there are no clouds in Wan Li, the sky in Wan Li is blue.