It's an interesting quote because Sartre is a known existentialist who is secular, believed in no god. Still, the mind of one of believes in the existence of a deity must find a certain peace, even beauty. We have a choice. We can either look upon the vast cosmos with despair as we perceive the flux of death and rebirth or see hope and order in things. I choose the latter. Maybe there is a God. I could be wrong and all good arguments are welcome.