The quote above is taken from Friedrich Nietzsche's great work Also Sprach Zarathustra. In this he presents a philosophy that has become known as the The Three Metamorphoses. I suggest that this proverb is how Nietszche aviods the pitfalls of the eternal return as suggested in his famous 'Demon' quote from The Gay Science. You will recall that this goes:
"What, if some day or night a demon were to steal after you into your loneliest loneliness and say to you: "This life as you now live it and have lived it, you will have to live once more and innumerable times more; and there will be nothing new in it, but every pain and every joy and every thought and sigh and everything unutterably small or great in your life will have to return to you, all in the same succession and sequence - even this spider and this moonlight between the trees, and even this moment and I myself. "