The river flow itself sustains, yet the same water never remains.
Bubbles float in the backwater; some are dissipated, some are generated, and none are stationary.
--- Kamo no Tyômei (1212): Hôzyôki (my translation from Japanese)
Kamo no Tyômei was a Buddhist monk, though his Kamo family were keepers of a Shintô shrine. His essay is one of the well-known Japanese classics. The title Hôzyôki means a record kept in a square house whose length of each edge was three meters (a quite humble house). He wrote about social and political phenomena from a somewhat distant but not completely transcendent position. The first two sentences are usually considered as metaphor of human life, but they also indicate that he was a watcher of natural phenomena.
The second sentence means the ephemeral nature of lives of individuals. It echoes the well-known Buddhist phrase of Syogyô muzyô or "Everything is transient." I use English mainly to convey scientific and technical information, so I just choose those words that are familiar to me in the translation, even though those may be unfamiliar words to native English speakers.
Though certainly he emphasized transience of individuals, he also mentioned that the individuals are members of something not so ephemeral -- a river in this case. I had not found an English word that would explain this concept for a long time. Recently, when I read a book about the concept called "sustainability", I found that was it. So I write the first sentence like this. It may be somewhat strange to use the verb "to sustain" like this rather than "is sustained", but by this way it can rhyme with "remains".
Something similar to the first sentence had already been said around 500 B.C. by Herakleitos, a Greek philosopher. The coincidence may be explained in several ways: They might be independent inventions; The words of Herakleitos might have been incorporated into Buddhist thought, perhaps in Gandhara; Or, the thought tradition of India that gave rise of Buddhism also influenced Herakleitos.
According to Herakleitos, however, the river cannot be the same one if the same water does not remain. On the other hand, it seems that Tyômei did not question the identity of the river. He must have known that the route of the Kamo River he probably watched (which also was the origin of his family name) had been artificially changed somewhat during the construction of the City of Kyoto some 400 years before him [Note]. So the river does not have any connotation of something eternal. It is just something that has a longer time scale than a bubble.
[Note] When I wrote this sentence, I thought that the original position of the river channel was near the center of what to become the city, and that the present river channel was purely artificial. According to YOKOYAMA (2004, the final chapter), this view, which was really held by historians, is not real. Geological analysis has revealed that the original position was not far from the present one. I revised my understanding accordingly. But, I still think that the construction of the city involved small-scale modification of the river channel. So I keep the sentence just with a word "somewhat" added.