This is widely attributed, in various forms, to Carl Sagan; but, I can't seem to find the actual quotation or the source.
"We are star stuff harvesting star light. Our lives, our past and our future are tied to the sun, the moon and the stars. [We are]...star stuff contemplating the stars, organized collections of ten billion, billion, billion atoms, contemplating the evolution of nature, tracing that long path by which it arrived at consciousness here on the planet earth, and perhaps throughout the cosmos."
~ Carl Sagan, "The Cosmos"
We are the dust of the universe, trying to understand where it is going and whence it came — sometimes through theology, sometimes through science, sometimes through a combination of both.
We are the dust of the Universe, trying to understand itself.
~ Charles R. Pellegrino, Ghosts of Vesuvius
"Then I will tell you a great secret, Captain. Perhaps the greatest of all time. The molecules of your body are the same molecules that make up this station and the nebula outside, that burn inside the stars themselves. We are starstuff, we are the universe made manifest, trying to figure itself out. As we have both learned, sometimes the universe requires a change of perspective."
~ Delenn to Sheridan in Babylon 5:A Distant Star