“The Hollow in the Stone” by W.S. Merwin

Not every kind of water will do
to make the pool under the rock face
that afterward will be clear forever

the loud current of great event
already far downstream in its moment
heavy with the dark waste of cities
not the water of falling
with its voice far away from it
not the water that ran with the days
and runs with them now

only the still water
that we can see through all the way
whatever we remember
the clear water from before
that was there under the reflections
of the leaves in spring and beyond
and under the clouds passing below them