One moon shows in every pool in every pool the one moon.
The symbol for the moon in Chinese is combined with the symbol for the sun to mean “bright” or “luminescent”. The harvest moon gets its name from the fact that it is so bright the farmers can continue their harvest well into the night, thanks to the plentiful light from the moon.
As such we can interpret this quote as the one light shows in each of our pools, or minds, and in each of our minds there is one source of light. This light is often a metaphor for enlightenment. Notice how the light, or moon, is already there, how it is extant in everyone’s pool, or mind.
This is referred to as Buddha nature, the fact that everyone already has it, and just needs to become awakened to this, or return to their inherent Buddha nature. It should not be as hard as many of us make it out to be. Try easier. Wu wei.